With the identity of the timeline-unraveling "thread" revealed, the team's mission to protect him at all costs leads each agent to question their own values. Is preserving the future of the world as they know it worth the destruction they could prevent?
Late at night, Alphonso Mackenzie drives the car with Deke Shaw and Freddy Malick who tells Mackenzie the Chronicom Hunters are gaining on them. Mackenzie turns off the car’s headlights and hides the car in the dark alleyway to lose the Hunters. Shaw tries to get in contact with Daisy Johnson via a walkie-talkie, but there is no response. With Mackenzie and Shaw looking, Malick takes out a green vial that has the HYDRA insignia on it. He then drops said vial back in the alcohol bottle. Onboard Zephyr One, Melinda May wakes up and checks her wound, which much to her surprise is all healed.
Meanwhile, back at The Krazy Kanoe, Phil Coulson and Johnson tend to an injured Viola. Shortly thereafter, Yo-Yo Rodriguez and Jemma Simmons arrive and Ernest Koenig begrudgingly lets the two women in. Coulson argues that they have to protect Malick so that HYDRA will form, because without its formation, S.H.I.E.L.D. doesn’t form in response. Johnson tries to persuade the group to kill Malick and alter the timeline, because so many lives could be saved as a result. But Coulson rebuffs that idea because something much worse could rise up in HYDRA’s place.
Enoch calls to let them know that May is awake now. A worried Simmons orders Enoch to sedate May and put her back in the healing pod. He tells May that she doesn’t look too good, and perhaps she should rest for a bit. May realizes she knows Enoch he says that she and him have not yet met in this timeline. May asks where Simmons and the others. Enoch explains that the team is on a mission.
The Chronicoms arrive at Koenig's bar looking for leads. With Viola now stabilized, Koenig hides the team in a secret chamber off of his office. The Chronicoms, Luke and Abel look around and are about to leave when the Viola regains consciousness. The team does their best to keep her quiet, but she accidentally tips over a wine bottle. Rodriguez is in a position to catch it but is not able to use her powers. The noise however alerts the Chronicoms. But before they could investigate further, it is reported that Malick’s car was located and they leave. Simmons notices a green droplet on Viola's shoe. Borrowing a knife from Koenig, she carefully scrapes it up and proceeds to examine it with her materials.
Now aboard the train, Mackenzie Malick about himself. He says he is just getting jobs, but Mackenzie still doesn’t believe that this is all about liquor. Malick smirks as he tells Mackenzie that whatever it is he’s delivering won’t change the world. Mackenzie and Shaw exchange looks knowing this is not necessarily true.
At The Krazy Kanoe, Simmons analyzes the green substance. As Simmons works, Johnson asks Rodriguez why she didn't catch the bottle. At first, Rodriguez claims she didn’t see it. Johnson calls her out on her lie. Rodriguez then admits that she couldn’t move, she froze, but admits she isn’t sure why. She theorizes that maybe it has to do with the Shrike infestation messing her up. Simmons exclaims she knows what the substance is. She explains that the substance was an ingredient in the very first Super Soldier Serum and Malick is about to deliver it.
On the Zephyr, May tries to leave in order to help the team. Enoch tells her she is in no condition to help them. Enoch points out that since May woke up, she does not appear to be acting like herself. He asks her how she’s feeling, to which May answers honestly that she isn’t feeling much of anything. He surmised that there may have been complications in her surgery.
After questioning Viola, she tells them if they want to stop it, they can go to hell. Koenig realizes a clue in her words and explains that Hell refers to Hell's Harbor. Viola smirks as she says that they will never get there in time, unless they can fly because there are no trains fast enough. Koenig says he will tell them where it is, but only if they take him along. Coulson tells him it’s not possible. He reminds them that Malick is his responsibility. Begrudgingly, they accept his terms. Meanwhile, the Chronicoms have arrived where Malick.
Back at the train, Malick pulls a gun on Mackenzie and Shaw saying once again he can’t let them look through the bottles he is transporting. He tells Mackenzie that he should listen to Shaw, because he just needs to do his job and then they can all go home.
Back on the Zephyr, May is going to leave to find Mackenzie and Shaw. Enoch apologizes as he says that he can not allow her to leave the ship and a fight ensues. Eventually, she gains the upper hand and starts hammering on Enoch with a fire extinguisher. Coulson and the team arrive and he tells May to stand down. She looks at Coulson for a moment and remarks that he is not Sarge. But he is not Phil Coulson either. The Coulson LMD asks May if she’s not the least bit surprised since he was dead. May tells him that Coulson still is dead as she walks away. Soon, she is back in the pod. Enoch points out that Agent May is clearly malfunctioning.
Coulson then takes the blindfold off of Koenig, who is astounded about what he sees. He begins to believe they are aliens. Eventually, Coulson admits that they are all from the future. At that moment, an alarm goes off, which Simmons explains that the countdown to a time jump has commenced. In 17 minutes the Zephyr will jump, whether they are on board or not. Coulson tells Johnson to contact Mackenzie and Shaw and let them know they are coming for them. Johnson gets a hold of Shaw. He tells her he is with Mackenzie and Malick. Johnson hesitates but then tells Shaw to take the shot to kill Malick. He is reluctant to as he is just a kid in his eyes.
Mackenzie looks through the rest of Malick’s liquor bottles and eventually finds the vial floating of the serum in one of them and proceeds to dump its contents on the ground. Mackenzie asks Malick what it is. He tells Mackenzie he doesn’t ask questions. He just did what he was told. Shaw then returns and he points his gun at Malick. Mackenzie tells him to put the gun down. But Shaw explains that Freddy is really Wilfred Malick. Mackenzie reminds Shaw that only he can give such an order and yells at him to put the gun down. Shaw hesitates, but ultimately ends up lowering his gun. Instead, Shaw shoots at the Chronicoms who have arrived on the scene disguised as the cops from earlier.
Mackenzie, Shaw, and Malick dive for cover as the Chronicoms open fire on them. Fortunately, Coulson and the rest of the team come rolling up in a car. Koenig and Coulson fire with their guns at the Chronicoms. But unbeknownst to them, Malick used the confusion to grab the vial and the gun and run off to make his delivery. Upon noticing his absence, Mackenzie tells Koenig and Enoch to find him. As the battle continues, Malick is elsewhere waiting for his contact to show up when Koenig also arrives. Malick points the gun at Koenig asking him to leave. Ultimately, Malick shoots Koenig in the shoulder. Malick’s contact arrives and he gets in the car and leaves. Enoch arrives and asks Koenig if he is alright. Coulson radios in and tells Enoch to get to the Zephyr, time is running out.
Coulson and the team arrive at the Zephyr with Simmons telling them to hurry. Only Enoch is missing. As the timer counted down, Simmons tells Mackenzie they need to close the hatch. As it close they could see Enoch sprinting toward them. They tell him to hurry but he arrives too late. In the end, Enoch finds himself back at Koenig’s bar working as a bartender.
- Clark Gregg as Phil Coulson
- Ming-Na Wen as Melinda May
- Chloe Bennet as Daisy Johnson/Quake
- Elizabeth Henstridge as Jemma Simmons
- Henry Simmons as Alphonso Mackenzie
- Natalia Cordova-Buckley as Yo-Yo Rodriguez
- Jeff Ward as Deke Shaw
- Joel Stoffer as Enoch
- Tobias Jelinek as Luke
- Darren Barnet as Wilfred Malick
- Nora Zehetner as Viola
- Patton Oswalt as Ernest Koenig
- Christopher Wallinger as Copper
- Eric Schloesser as The First
- Kevin Alexander Stea as The Second
- Gina Gonsalves as The Third
- Ryan Gray as Abel (uncredited)
- New York City, New York
- Hell's Harbor
- Hamburg, Germany (mentioned)
- Hamburg Airport (mentioned)
- Bremen, Germany (mentioned)
- Bremen Airport (mentioned)
- Berlin, Germany (mentioned)
- Berlin Tempelhof Airport (mentioned)
- Canada (mentioned)
- London, England (mentioned)
- Copenhagen, Denmark (mentioned)
- Newark, New Jersey (mentioned)
- Newark Liberty International Airport (mentioned)
- Moon (visible; mentioned)
- Mars (mentioned)
- Fear Dimension (flashback)
- Duel on Zephyr One
- War Against the Chronicoms
- Izel's Campaign (flashback)
- Battle at the Temple of the Forgotten (flashback)
- World War II (mentioned)
- La Respuesta
- Yo-Yo Rodriguez's Prosthetic Arms
- Healing Pod
- Chronicom Rifle
- Super Soldier Serum (key ingredient)
- Shrike (mentioned)
- Chronicom Hunters
- New York City Police Department
- Royal Canadian Mounted Police (mentioned)
- Leo Fitz
- Wilfred Malick's Parents
- Abraham Erskine
- Red Skull
- Phil Coulson
- Gideon Malick
- Ernest Koenig's Grandchildren
- Butterfly Effect
- The title is said twice within the episode, by Ernest Koenig when referring to Jemma Simmons' chemistry know-how, and by Enoch when referring to his knowledge in drink mixing.
- When Koenig hires Enoch, he says theirs is "the beginning of a marvelous friendship." This quote is a take on the last lines of the 1942 film Casablanca ("Louis, I think this is the beginning of a beautiful friendship"), with the substituted word acting as a reference to Marvel.