Airs. Sundays 9:00 PM on TNT (US) Report Top. A recap of TNT’s ‘The Alienist’ finale episode 10 starring Daniel Brühl, Luke Evans, and Dakota Fanning. Continuing. A killer is stopped. Recap guide / thumbnail previews for "The Alienist" Season 1 Episode 10 . Next episode. S SEASON 1 E EPISODE 10. “Castle in the Sky” is a surprisingly bright conclusion. Season 1, Episode 10: ‘Castle in the Sky’ The series finale of “The Alienist” depicts what came to be known a century later as a “ catastrophic success.” A child is saved. Status. TBA. SIGN IN Recaps for TV shows View TV episodes as 50 thumbnails The Alienist.