The Odyssey crew gathers in the brig, learning all they can from Annorax. The reason? Kalen’s been leaving the details of their trials in a temporally shielded probe, and discovers suddenly that there are hundreds of file fragments – along with one of Kalen, shouting instructions. They’ve been stuck in a time loop for a while now, endlessly dying trying to stop the weapon-ship. Worse, they learn from the captured ship captain that the weapon is heading for the fleet to obliterate them. The Odyssey leaps to warp, racing to help their allies.

The team of Selveth, Kalen, Domino, and Vulmos study all the information gathered. Between Annorax’s knowledge, the blueprints, the file fragments, and disabling the safety limits of simulations, they assemble a plan of attack. It’s incredibly risky, but despite the odds, Captain Chang orders it to be set in motion.

When they arrive, they see the weapon-ship menacing the fleet. The ves’Targ, its open hail featuring the ship’s bridge crew singing a Klingon Opera, attacks the Krenim weapon immediately, drawing its attention. Their remaining allies screen the fleet while the Odyssey itself careens at the weapon, ready to enact its plan. Fire pierces the shields, damaging the saucer and the the ship’s star drive section, as well as one of the warp nacelles. But Domino keeps her course and Kalen keeps the engines running long enough for Commander Adams to fire a series of modified torpedoes. His salvo pierces their shields, damaging the temporal core enough to render it vulnerable. With another precisely aimed torpedo, Adams destroys the ship’s core.

The plan now falls to Domino and Kalen. Both pilot and engineer volunteered, briefed on the fact that protecting the crew from the temporal changes requires them to do this without shielding to prevent a paradox. Exposed to the coronal implosion, Domino pilots the Odyssey directly into a space-time breach formed by the implosion.

The bridge freezes save for Domino and Kalen. Domino’s mentor (long thought dead) steps out, now a being known as a Traveler. He explains that he’s been trying to lead Domino here to solve this problem, and the pair’s solution needs only a cosmic nudge from him to succeed. He offers to solve it, and return things to some semblance of normal, in exchange for them accompanying him beyond this reality. Domino agrees without hesitation, and after consideration, Kalen does as well.

The Traveler unpauses the rest of the bridge so that they may say goodbye. After the explanation and confirmation that both are interested in the offer, the Captain affirms that it was an honor to serve with them, and the trio of Travelers leave.

They pass through the breach and everything is calm again. Sebastian has returned, the Tiro is in the bay, the colony ship has even avoided the catastrophic damage from the jump to this sector. However, occupying the time loop means that nine months have passed outside of it.

Light two members of the family, those remaining on the Odyssey set a fresh course home, the fleet following behind.

The Odyssey licks its wounds after the skirmish with the weapon ship, and Captain Tchang is becoming increasingly focused on dealing with this Krenim superweapon as it continues taking lives around them.

Selveth visits the captain privately – she isn’t the confidant that Sebastian was, but she is a scientist, and thinks she can merge a shuttle’s shields with the temporal stasis field that protects the weapon-ship. The captain asks for volunteers for a rescue mission for Annira, and the first two to step up are Selveth and Kalen. The team decided, Adams is placed in command of the ship and they begin preparations.

The second Type-9 shuttle onboard, the Volga, is modified. The shield systems are tuned to the weapon ship’s, the chroniton warheads from the troop transport are moved into its torpedo launchers, and the captain has Kalen set a remote self-destruct for the shuttle – just in case. Kalen rigs up life support belts with temporal shielding, and the group departs from the Odyssey.

They’re able to follow the weapon ship’s ion trail, and Kalen is able to mask their warp signature in order for them to fall into the ship’s warp wake and follow along. As they maneuver to get into the field though, the ship abruptly drops out of warp to change course, and the turbulence causes the Volga to veer more than a thousand kilometers away from the weapon – who spots them and starts hauling them in via tractor beam.

While the shuttle is tractored in, Kalen acts quickly, utilizing the shuttle’s transporters to relocate them aboard the ship, near Annira. Once freed, the operations manager also frees an older Krenim man named Annorax, who claims to be the designer of the weapon. For the moment, the ship isn’t aware of their presence on the ship, having towed an empty shuttle into their launch bay.

Kalen proposes breaking the group into three, and all heading for the temporal core. There, whoever reaches the core can use their tricorder as a targeting beacon in order to beam one of the shuttle’s chroniton torpedoes to the core, hopefully disabling it. Selveth and Annira head for the computer systems, in an attempt to provide overwatch. Kalen and Annorax make for the core, with the captain taking another route solo.

Kalen makes good use of Annorax’s knowledge of the ship, managing to stay largely hidden. He’s also able to make a backdoor in their security systems with minor assistance from Annira. The Romulan and his Krenim ally arrive at the core, and after a few scans, Kalen places his tricorder for maximum effect before heading back. On the way back, as though fate were displeased with his success, Kalen runs into a group of Krenim security. But quick thinking (and an excellent shot at a wall power tap) disables the group and Kalen calls to the away team to evacuate.

The captain, meanwhile, has gotten involved in a firefight. She found Obrist, the commander of the ship, and the two exchange fire while he calls for backup. The jig up, the Captain finally manages to stun Obrist and hauls him along with her to the launch bay, where they all pile into the Volga and blast off as they trigger the torpedo transport.

The shuttle gets clear of the weapon and the Captain sets up an attack run on the temporal core just as two Krenim warships drop out of warp, protecting the weapon. She attempts to threaten Obrist to make the Krenim withdraw, but discovers the Krenim Imperium isn’t aware of the movements of the Weapon ship – whatever the weapon’s mission, it acts independent of the Imperium. The second torpedo is fired to distract the warships as the Volga retreats. The weapon still survives, but Annira is now safe – and they have the weapon’s designer aboard.

The Captain’s using the Holodeck, having an unproductive session with a holographic therapist, when Annira calls from the bridge – their probe reports the weapon is moving. It destroys the probe and sets course their direction.

The fleet is rearmed, and the Odyssey leads the strongest ships to a neighboring polity, the Nihydron. On the way they see the weapon-ship on long-range sensors, and contact the other half of the fleet, scattering them and setting a rendezvous in a few weeks’ time. The anchorage is vaporized by the weapon ship, which gives chase to the Odyssey’s portion of the fleet.

After dodging Krenim patrols at the edge of Nihydron space. An unexpected skirmish with a Krenim warship in a nebula shows the crew their temporal shielding isn’t completely effective against their chroniton torpedoes, and one of the appropriated Zahl cruisers, captained by Carela Tann, peels off to fight them, disappearing into a nebula. She doesn’t rejoin the fleet, and they’re forced to move on without one of the cruisers.

The rest of the detachment meets Admiral Traken of the Nihydron. He and his eighteen destroyers have been holding off the Krenim for months, and they’re willing to assist in bringing down the weapon-ship. The coalition realizes that the weapon ship is tracking the Odyssey, and use it to spring a trap on the weapon.

It shows up, five times as long as the Odyssey, and hails. Its commander, Obrist, declares them an anomaly, and quickly reveals his intent to remove them from time. Before doing so, he somehow transports Selveth and Annira off the bridge, and then fires its temporal weapon. Interceding, Kalen overcharges the ship’s shields, which prevents almost all of the damage. The weapon’s beam strikes the remaining Zahl cruiser and it disappears. The Nihydron attack, as well as the ves’Targ, though few of their weapons seem to impact the weapon-ship’s temporal shielding. Having planned ahead, Kalen and Parker have modified five torpedoes with the same chroniton module of the Krenim’s weapons, taken from the troop transport they appropriated. Working in tandem with the on duty Conn officer Ensign Casse, Parker concentrates torpedo fire on the weapon-ship’s temporal core. The fight is serious, with heavy losses for the Nihydron, but the temporal core is temporarily disabled, and Kalen is able to transport Selveth off of it, but is forced to leave Annira behind. The weapon-ship seriously damages the Odyssey’s port nacelle, disabling warp drive, and then escapes. When the chaos quiets, a damaged Odyssey, the ves’Targ, and four Nihydron ships remain.

The timeline has changed. Sebastian died at the beginning of their mission – Selveth took over as XO. The Tiro was destroyed, the Sikarians are divided… Many things are the same, but many things are different. The chroniton wave, triggered by the Krenim weapon, affected everything, including the fleet.

The discovery that the fleet experienced a shift to a new timeline prompts Captain Tchang and the crew in the know to prepare to track down the weapon that caused the timeline change, and stop it from activating again. The Captain orders the fleet to retreat to a chaotic space anomaly nearby, using its effects on space as a place to hide while the fleet affects repairs. Leaving the ves’Targ to watch over them, the Odyssey separates from the fleet and starts investigating, heading first to the site of the first weapon detonation. Kalen establishes temporal shielding like the ves’Targ’s, and builds the tech into a handful of life support belts for an away team to be protected.

Arrival at the system where the weapon was used is heralded by severe subspace turbulence. Domino safely brings the ship out of warp, and the sensors and science teams aboard the Odyssey get to work. Analysis starts by comparing the system in two timelines, thanks to Zahl records before and after the timeline change – and the system’s third planet is missing. Celestial events in the system were altered by this, and the star is now dying. They do detect something though – an ion trail, seemingly fixed in time, not decaying. They can track the culprit.

With the temporal shielding only just working, the ship opts not to immediately engage the ship. They know too little, but at least now they can keep an eye. The ship launches one of its multispatial probes, using it at a distance to track the superweapon while they investigate further. With the intel they gained on Zahl, they identify a research station behind Krenim lines that is pursuing temporal research – that becomes their next stop.

Managing to avoid Krenim patrols, the Odyssey drops out of warp hidden behind one of this system’s two gas giants. The station orbits the other. Parker assembles an away team of Domino, Kalen, and Vulmos, and the four take the John Stewart over in order to learn what the Krenim have created. They stealthily beam aboard and take some readings, learning quickly that the station is civilian – none of the 13 Krenim aboard are armed, and none are wearing uniforms. Emboldened by the lack of obvious resistance, Parker leads the team to contact the researchers in person. Domino takes the lead, her genuine curiosity about their research and her honesty about not being from this timeline disarms the civilians, and they wind up investigating the chroniton residue left on the crew from their interaction with the weapon on Zahl.

The crew learns much – this timeline ceased research into temporal incursions, the weapon that removed that planet from time. A scientist 200 years ago named Annorax developed two incredible (and highly dangerous) theorems relating to time. The first was the method of creating incursions, and the second was a method of arresting entropy, preventing aging, systems breaking, or things decaying. Thanks to the Krenim building computers that exist slightly out of phase with normal time, the crew locates incomplete technical specs for the weapon Annorax intended to design. The ship itself is equivalent to Kirk-era tech beyond the weapon and its shields, which use the entropy arresting effect to prevent any weapons from penetrating its defenses.

They don’t have much time to process the information, as the Odyssey informs the away team that Krenim scouts are on the way – Krenim sensors aren’t as good as the Odyssey’s, so they have a narrow window to escape. Chief Hegrom starts to beam them up just as the station’s shields go up, almost trapping the team if not for the chief’s experience completing the transport around the interference. The station hails the Odyssey, and one of the senior researchers curses Captain Tchang and the Odyssey, calling them filthy aliens. She was the one who alerted the military, and the Odyssey leaves before they get close.

Their presence now known to the Krenim, the ship considers its options and heads for a Zahl anchorage in the records they retrieved. The possibility of munitions, fuel, and other tech would be a boon since in this timeline the Odyssey has half the torpedoes they did. The Anchorage sits on the far side of an energetic nebula, and after getting singed a bit heading through, the Odyssey finds the anchorage – along with a Krenim strike team boarding it.

Parker gathers another team – himself, Domino, Kalen, and Lt. Mackenzie. The Odyssey confirms that the Krenim’s troop transport is empty, and they’re the only life signs aboard the anchorage. So the team beams to the transport itself, docked with the station. Investigation confirms that the Krenim happened upon the secret base and are preparing to scuttle it with charges. Thinking quickly, Parker asks the chief to beam the charges planted into space. One activated one is beamed out a soldier’s hand, which alerts the soldiers to intruders. They race back to their ship, only to see it flying back toward the Odyssey, with the away team waving to the soldiers as they depart. Stuck on an airless base with limited oxygen available, it’s a quick process to prompt the soldiers to surrender and take them into custody.

Time now on their side, the crew takes inventory, and learns the true value of this anchorage – in addition to hundreds of photon torpedoes, weapons, antimatter, and spare parts, two Zahl heavy cruisers were docked here for repair, and the two thousand refugee Sikarians aboard the Odyssey are ready to get their hands dirty making them spaceworthy. Captain Tchang contacts the fleet and provides the location for the anchorage while the rest of the crew begins the fastest refit possible. The Krenim patrol won’t be missed for another two weeks – they have that long to prepare for war.

Captain Tchang assembles an away team consisting of herself, Adams, Selveth, and Kalen. The four join Plogh aboard the ves’Targ and range ahead of the fleet as they mend their wounds. They make contact with the Zahl via subspace, who invite them to their planet to trade and exchange information. The trip is several days at warp speed, but it passes uneventfully.

Cleared for landing by Trade Minister Paajik, the ship is landed proficiently by the ship’s newly minted pilot, Heklara. As they land though, a tremendous flash temporarily blinds the view screen, and as the ship touches ground, they are no longer where they were. The tiled buildings of the arid planet were now smashed into rubble and ruin after orbital bombardment.

Using a probe borrowed from the Odyssey and what little the sensors could provide through the sudden spike in unusual radiation, the crew learns a little. First, that some distant event outside the Zahl system caused a chroniton wavefront to sweep through it, altering things immensely. The Zahl homeworld now seemed conquered by their Krenim neighbors, and several upgraded Krenim warships now orbit above. The timeline has been changed.

In search of more information, the team departs the ship to visit the half-destroyed government building they landed near. Selveth stays behind to analyze all they have learned. Inside the building, they find freedom fighter Paajik, who they convince to provide them with coordinates to a cache of governmental records and data. They grab survival gear and head off, carving a path toward their goal via the Captain’s navigation skill and the rest of the team’s combined skills in fire team tactics. They recover Krenim Comms after ambushing and knocking out a patrol, and make it to their goal, where Parker briefly channels his agrarian roots and digs up the cache. The team copies the data and returns the cache – just in case these changes are permanent, and the records are still useful to the Zahl.

With all the information they can gain at hand, the crew makes a stealthy retreat to the Raider. With more pieces to the puzzle, including detailed scans of the Krenim patrol’s weapons, more theories emerge. The Krenim may have developed some form of time-altering superweapon, and it should have affected the ves’Targ, if not for an experiment Selveth had brought aboard with her – a fluke, but useful knowledge.

A daring escape involving their last probe and the sacrifice of an unmanned shuttle gets the ves’Targ clear of the Zahl homeworld and they arrive back at the fleet – and it isn’t long before they notice things are different. When the Captain steps upon the bridge, the biggest change is evident – Commander Sebastian is dead!