In the fourth episode of the fifth season of Star Trek: Discovery, the action kicks off with Moll and L’ak engaging in a shady encounter with a duplicitous dealer, fifteen hours prior to the main events. They present him with a sack filled with platinum, and when he attempts to jack up the price, Moll reveals her cunning ploy: the latinum is poisoned, and as the dealer succumbs to the toxin, Moll swiftly retrieves the item from his grasp. L’ak, still tentative, receives assurances from Moll that they are on the verge of outpacing the USS Discovery. She declares confidently that once they secure the Progenitor's technology, they will be free from all constraints. Moll urges L’ak to hasten their pace to intercept the Discovery on Trill, revealing that the device they obtained from the dealer is identical to the one covertly planted on Adira Tal in the closing moments of the previous episode.
Elsewhere, the device springs to life within Adira's quarters on the Discovery. It detaches from her uniform, darts across the room, and vanishes into a girder, eluding detection. In his laboratory, Stamets spies the mysterious bug and watches in amazement as it disappears into the wall. Meanwhile, Burnham receives a report from Owo, alerting her to odd readings and the broadcast of a signal emanating from the ship. Burnham and Rayner attempt to teleport to the bridge, but they find themselves stranded. The ship is in motion, yet the lights flicker erratically and a klaxon blares, filling the air with a sense of panic. Rayner wonders if they are under attack, as Burnham frantically tries to establish contact with the bridge, but all attempts seem futile.
Burnham and Rayner hurriedly traverse to the bridge on foot and are horrified to discover the rest of the crew unconscious, clad in 23rd-century Starfleet uniforms. Rayner and Burnham realize with a jolt that they have somehow entered a wormhole and been transported back in time. The Discovery seems to be following Burnham's trail as she inadvertently navigates through the wormhole into the future. It transpires that they have not merely traveled back in time, but are actually leaping through the fabric of time itself.
Rayner speculates that they have encountered a rare time-manipulating parasite known as a "chronophage." He explains that these are relics from the Temporal War, designed to disable enemy vessels by causing them to cycle chaotically through different eras. Burnham suspects that Moll and L’ak are somehow involved in this temporal anomaly, and the mystery deepens as they scramble to unravel the truth and find a way to restore the timeline to its original course.
The relentless time jumps persisted, and Burnham realized that merely tracking the cycles was insufficient. Zora suggested delving deeper into the data, highlighting the significance of variables like the ship's location, distance traveled, and speed. Burnham zeroed in on speed, as their journey entailed traversing not just time but vast expanses of space.
By meticulously measuring Discovery's speed against the lengths of the time cycles and factoring in additional dimensions, a pattern finally emerged. It was a conical wave, a rhythmic undulation that seemed to govern their unpredictable leaps through the timeline. Just as they decoded this pattern, another time jump occurred, verifying their discovery's accuracy.
Rayner clung to the hope that they might emerge in an era where Stamets was still alive, his expertise a potential lifeline in their increasingly complex predicament. Eventually, Burnham materialized in the future, explaining the dire situation and her crucial mission for the future incarnation of Discovery.
As she recounted her intimate knowledge of the crew, including Airiam, Tilly, and the others, their confusion slowly morphed into suspicion. However, Burnham's resolve was unwavering. She recounted witnessing Airiam's demise and recounted the climactic events of "Project Daedalus," her words painting a vivid picture that gradually won over the skeptical crew.
Airiam, convinced of Burnham's authenticity, inquired about the assistance she required. Meanwhile, Rayner shared his own tale of Burnham's arrival on the bridge, feeling like an outsider amidst the familiar faces. He assured YB that she belonged there, urging her to trust her instincts, even as they screamed for caution.
Suddenly, Discovery's warp bubble ruptured, forcing Rayner to hastily deploy the device on the chronophage. Another time jump ensued, and they emerged back in the present, a world that seemed miraculously intact.
The episode concluded with the rest of the crew catching up on the chronophage's progress. In the fleeting six hours since the time jumps began, the DOTs had managed to detect a warp signature matching M'ak's vessel. Rayner praised Rhys for his theory, which had proven prescient. However, the trail of M'ak quickly vanished, leaving Burnham to order the bridge crew to embark on solving this new mystery, a challenge that promised to be as intricate as the time jumps themselves.
