Oliver, Dinah, and Quentin are investigating an area where Cayden may strike next. Cayden manages to kill a team of ARGUS agents who were trying to track him from under the water.
At the Mayor's office, they have at this point wired $70 million dollars to Cayden's account. Oliver and Thea know that this is only going to get worse.
The next day, Quentin is walking down the streets until he notices that Black Siren is following him. Later that night, Dinah meets with Vincent as their conversation leads to a make-out session.
In a flashback from five years ago, Vincent and Dinah are introduced to each other for the first time. This was when they first became partners as members of Central City Police Department.
Back in the present, Vincent meets up with members of the cabal. Cayden expresses that he feels unsure whether he can trust certain members on his team.
Oliver meets up with Felicity at the bunker where she has been trying to find Cayden. They spot Vigilante being on the move as Team Arrow goes after him.
They try to shoot him down, but Mister Terrific and Wild Dog stop them. They tell the Green Arrow that Vigilante was there to meet them as they are working together.
The two teams meet up with Vincent present as Oliver is questioning whether they can trust him or not. He begins to ask Vincent questions about what heads up he can give them.
At city hall, Thea and Quentin are trying to find more resources for the next payment to Cayden. Quentin tells Thea about Earth-2 Laurel following him lately as he is not sure what to make of it.
She suggests that they need to find a way to reach out to her. Back at the other team's bunker, Oliver pulls Vincent to the side to make it clear that he doesn't trust Vincent at all.
In another flashback, Vincent and Dinah are undercover on a case. Back in the present, the former members meet up with Team Arrow at the bunker to get ready.
Vincent manages to get into the server room thanks to Felicity. But Cayden catches him sneaking in and suggests they have a little talk.
While the team is copying the information, they listen in to the conversation between them. Felicity tells Vincent what to say to Cayden to buy them some time.
In another flashback, Dinah and Vincent are almost caught. Back in the present, Vincent is trying to leave but is stopped by one of Cayden's men.
Vincent transmits the download to Team Arrow and rushes away. In another flashback, Dinah tries to calm Vincent down as he is worried that they have been caught in their cover.
Back in the present, Cayden stops Vincent as he knows that he is the traitor. Back at the bunker, Alena is helping the team trying to decode the files.
In another flashback, Dinah is caught as being undercover. Back in the present, Vincent wakes up as he is cuffed up while Cayden confronts him about he has been doing as the Vigilante.
With the help of Ricardo, he begins to torture Vincent to get some answers. But Vincent keeps denying the accusations as Anatoly uses some Russian methods to torture Vincent.
Quentin tries to lure Laurel out as she is following him again. Quentin confronts her but tells Laurel that he only wants to talk.
He begins to show Laurel the life of Earth-1 Laurel, the hero she was as the Black Canary. Quentin believes that she can be saved, but Laurel gets overwhelmed and runs off.
Back at the bunker, the team gets contact with Vincent again through his comm. But they are only hearing him scream as Dinah wants to take off and save him.
Oliver refuses to go on a risky mission as Dinah takes off with her team. Team Arrow head to the warehouse where the bomb is at.
Green Arrow finds a group of hostages as they are stuck in a room with a bomb that is close to detonating. Black Canary finds Vincent who tells her that he wasn't the one that turned his comm back on.
The bomb goes off as Dinah gets stuck underneath heavy blocks. Cayden, with the help of Black Siren, stops Vincent from helping her.
For a second, Black Siren seems reluctant to following Cayden's order. In another flashback, it is the night they were both given their abilities through the particle accelerator explosion.
In the present, Black Siren uses her cry to kill Vincent. Once the job is done, Black Siren leaves with Cayden. The team gets Dinah out of the block as she grieves the death of Vincent.
Later on, Felicity tells her team that Vincent didn't make it. Alena has finally cracked the files and finds the "evidence" that Cayden got to believe Oliver killed his son.
Thea tells Quentin that maybe they were wrong about this Laurel as she killed Vincent. Oliver goes to see Dinah see how she is holding up.
But she doesn't want to hear anything he has to say. He explains that they may have found a way to fight Cayden. But she doesn't listen as Dinah believes that the only way to end this is killing all of them, starting with Black Siren.