Which season and episode was it wherein...?

Angelus was stuck in Angel's memories или something and in the end Angelus and Энджел had to fight for either one of them to go on living in the body? Энджел saved a child's щенок at one point. I think...Cordelia?...was with Angelus in there watching those events.

Which season and episode was this? I'm sure it was on Энджел and not BTVS, as it was all about Angel.