In "Swim Deep" Debra has to do some lying and evidence stealing to protect her brother, which she obviously finds morally unacceptable, and Dexter finally comes to learn that he is on Sirko's killing list, but I don't think he realizes yet how wicked his newly discovered enemy really is.
- Dexter's cleaning his boat chitchatting with his father's ghost as usually, and finds some blood. Back in the lab he learns that this blood belongs to Lois.
- Debra finds out about the blood slide LaGuerta found in the church.Apparently, Maria ordered a test from another lab because she did not want her colleagues to think she was crazy for not believing that Doakes was a serial killer and because according to the Bay Harbor Butcher profile, he must be working for Miami Metro. She gives the case details to Debra, for her eyes only, but of course Debra shows it to Mr. Butcher himself.
- Dex comes back to his place, but before he opens the door, he notices that the curtain is not the way he left it, which means that someone was or still is inside. And we know who that is, right?
- So Dexter leaves a message on his autoreply, making Sirko believe he's gonna be in some cafe. Sirko goes there and receives a phone call from Dex. During the conversation, Isaak reveals that he wants to kill Dexter and his colleagues from police, including Deb, to avenge Viktor's death.
- To protect his sister, Dexter has to tell her about Isaak and Baskov. She gets upset as she learns that Dexter hid the fact that he found Viktor's fingerprint in Kaja's car.
- Hannah McKay helps Miami Metro find the bodies of one couple allegedly killed by her ex, Wayne Randall. As Dexter inspects the bodies, he realizes that Hannah was not only the associate of Wayne, she committed murders herself as well. However, DAs gave her immunity on all crimes committed with Randall, so she doesn't blink as he tells he what he' learnt.
- Debra and Maria visit the family of one of the Dexter's victims, a wedding photographer. On one of the photos Debra sees Dexter and hides it from Maria.
- Sirko follows Dexter to the den of a Colombian drug cartel, the group that is not fond of Koshka Brotherhood. Dexter believes Isaak gets killed there, 'cause he's outnumbered, but Sirko is extremely skilled, so he takes everyone down. During this slaughter, Sirko spills his own blood, which allows police to identify who he is, and so he gets arrested.
|Look how awesome he is!|
- Sirko and his company give some cash to Quinn, not really sure at this point, what for.
- Dexter visits Isaak in jail and listens to his story about his grandfather's revenge, which does not feel plausible in any way, but we get the main idea: this isn't over.
- Debra tells Dexter she doesn't want to know any more of his dark passenger stuff, she doesn't want to be a part of this anymore. So, metaphorically speaking, she wants to stay near the shore, while Dex swims deep.