Greys Anatomy Season 6 Episode 20 (Greys Anatomy s06e20) with title “Hook, Line and Sinner” airs on Thursday, April 29th 2010 at 09:00 pm via ABC Network. In this 20th episode, you can watch Sloan returns to Mark’s apartment, just as she’s going into labor, and Teddy, Mark and the still-fighting Callie and Arizona are there to help with the birth and to get Mark through his grandson’s pending adoption.