[Originally aired on October 29, 2017 on CBS All Access.]

Burnham is feeling at home on the Discovery although there is a party planned for the crew and she is uncomfortable with social gatherings.

At the party, there is a strange light flicker that disrupts the festivities for a moment. Burnham points out that there should never be a flicker on the Discovery but Tilly is more interested in setting her up with Tyler.

Burnham and Tyler are summoned to the bridge but collide with Stamets and Culber on the way. On the bridge, the crew discover a gormagander creature in their flight path. When they realize it is injured, they beam it into the shuttle bay for transport to a shuttle. While examining it, its mouth opens and a masked intruder comes out and starts firing on the crew.

The intruder turns out to be Harry Mudd and he threatens to kill Lorca as many times as possible in his plan to sell Discovery and her secrets to the Klingons just before he detonates an explosion that destroys the ship.

Time flashes back to the crew party. This time, Burnham and Tyler do not collide with Stamets and Culber but Stamets runs up to them and rants about how it all starts with a gormagander. When they reach the bridge and the gormagander is identified, they are wary about bringing the creature aboard despite Saru insistance on protocol.

Lorca beams the creature on board and Tyler accompanies Burnham to the shuttle bay. There is no intruder emergence this time but Mudd takes over Engineering and tries to force them to tell him how to run the spore drive before it overloads and blows up. He is incapacitated by Stamets. Unfortunately, Stamets informs them that they have done this repeatedly and he has yet to figure out how to prevent the drive's explosion.

Flash back to the party where Tyler asks Burnham to dance before the summons comes in. Stamets tracks Burnham down this time as she heads to the gormangander and prevents her from going to the shuttle bay. Lorca is summoned to the sick bay but is hijacked by Mudd.

Elsewhere, Stamets convinces Burnham about the time loop which lasts just about thirty minutes. As the thirty minutes nears its end, he asks for a secret so that Burnham will immediately believe that they have had the conversation before.

Mudd takes Lorca into his personal laboratory space, tells him he's killed him fifty-three times already, and then kills him again. 

Flash back to the party where Stamets approaches Burnham immediately and convinces her about the time loop. She doesn't manage to get information about Mudd from Tyler so she and Stamets dance and talk until the thirty minutes elapses.

Flash back to the party and Burnham drags Tyler onto the dance floor after speaking to Stamets. While dancing, she talks to Tyler about Mudd and the time loop and he kisses her. They ignore the summons to the bridge and Tyler remembers Mudd bragging about robbing a Betazoid bank. From his description, Burnham realizes Mudd has a time crystal and a four-dimensional species must have perfect a time loop technology powered by the crystal and sold it to Mudd (or he stole it)

On the bridge, Mudd sends Lorca to the brig, assumes command of the ship, and kills Lt. Tyler before Stamets jumps in and admits he's the missing element to the spore drive. Tilly and Burnham find Mudd's ship and the main time crystal technology hidden inside the gormagander and need Mudd to reset the time loop again. Burnham approaches him and tells him that although the Klingons will pay a lot for the ship, they'll pay more for her because she killed T'Kuvma. Once Mudd realizes what she's worth, she kills herself and he resets the time loop.

In this final reset, the bridge crew are prepared for Mudd when he enters the bridge. Lorca makes a deal to hand over Discovery, Burnham, and Stamets in exchange for the lives of the crew. Mudd lets the time loop elapse, the crystal tech dissolves as the Discovery and Mudd rejoin the time stream for good. 

Thinking the Klingons are beaming aboard to pay him for the Discovery and Burnham, he leads her and Stamets to the transporter room. As they approach the transporter room, they engage him in a discussion about his beloved Stella and reveal that they know he is actually running from her and her father. Instead of transmitting coordinates to the Klingons, they were sent to Stella and her father who transport on board to take custody of Mudd.

Burnham and Tyler have an awkward conversation on the lift about their relationship. Burnham ends with a personal log entry feeling better about her relationships.