Plot summary
Alison reveals to Vic that she let Aynsley die, then learns he is Angela's informant. Vic promises not to tell Angela if he sees Sarah. Sarah sees Vic at rehab, but Felix has drugged him, and he collapses. As Alison and Felix hide Vic, Sarah is mistaken for Alison and is forced to attend "Family Day," ultimately resulting in Donnie finding out about the clones and that Alison was telling the truth about being probed. Mrs. S and Paul arrange a meeting between Rachel and Ethan. After Ethan tells Rachel of her mother's fate, Rachel fires Leekie, and also implies to him that Dyad will be after him.
Cosima is angry with Delphine for using stem cells from a tooth Kira lost during the car accident. Kira willingly decides to give Cosima another tooth for analysis. Donnie goes to confront Leekie for lying to him and accidentally shoots him in the head.
Credits
Adapted from Wikipedia contributors, List of Orphan Black episodes. HTML formatting and reference markers removed.