In this recap by Ella James on Philly Buzz, “‘Swim Deep,’ the fifth episode of season 7 of Dexter, is one of the fastest episodes of the season, and the hardest to watch if you’re in favor of Dexter. Lt. LaGuerta is starting to close in on her search for truth about the Bay Harbor Butcher. She’s getting so warm that Deb offers to help and finds herself saving Dexter when she and LaGuerta visit the son of one of Dexter’s victims and Deb hides a photo with Dexter in it! Dexter visits his boat and realizes someone’s been killed there! After analysis, he realizes it was Louis and figures out that the Ukranian mob is now after him. He and Isaak play a dance of who can outsmart who. Dex comes home and realizes Isaak’s in his place so he leaves a fake voicemail sending Isaak to a restaurant and then calls Isaak in this safe spot for a game on! Dexter realizes Isaak is after revenge and he ends up keeping Deb safe in a hotel. While at a dig site looking for more ofWayne’s victims, Dex realizes Hannah isn’t as innocent as she is playing. He stays quiet. Why? Will there be a romance here? As Dexter leaves the dig site, he notices Isaak following him. Acting quickly, Dexter leads Isaak into a bar full of Ukranian enemies! Later, Miami Metro is called to the bar but Isaak’s body is not one of the victims. Isaak ends up in jail for murder and Dexter pays him a visit to find out this isn’t over.”
Also in this episode Deb steals, from evidence, an incriminating picture of Dexter at a wedding reception before one of his kills. She basically saved Dexter from getting caught. She then tells Dexter that she knows he will not stop killing and now she will not try to stop him as long as he does not interfere with active criminal cases. Finally Dexter is free to kill again.