After having a huge night in the ratings last week, “Smallville” and “Supernatural” continue their seasons this week with all new episodes, Thursday on the CW.

SMALLVILLE” — (8:00-9:00 p.m. ET) — Episode: “Abyss”

BRAINIAC ERASES CHLOE’S MEMORY — Brainiac begins removing Chloe’s (Allison Mack) memories one by one until the only person she remembers is Davis (Sam Witwer).  Clark (Tom Welling) realizes the only way to stop Brainiac from taking over Chloe’s mind is to rebuild the Fortress and ask Jor-El to heal her.  Erica Durance, Aaron Ashmore, Justin Hartley and Cassidy Freeman also star.  Kevin Fair directed the episode written by Don Whitehead & Holly Henderson (#3T7458).

SUPERNATURAL ” — (9:00-10:00 p.m. ET) — Episode: “I Know What You Did Last Summer”

SAM AND DEAN MEET ANNA, A GIRL WHO CAN HEAR THE ANGELS — Ruby (guest star Genevieve Cortese) tells Sam (Jared Padalecki) and Dean (Jensen Ackles) that a powerful demon named Alastair (guest star Mark Rolston) is searching for a girl named Anna (guest star Julie McNiven) who can hear the angels’ conversations.  The three set out to find Anna but once they do, Alastair attacks them and Ruby escapes with the girl.  Believing they were set up, Dean lashes out at Sam for trusting Ruby, so Sam tells him what happened during those months Dean was in Hell and how Ruby saved his life.  Castiel (guest star Misha Collins) and Uriel (guest star Robert Wisdom) return and demand to be taken to Anna but not for the reason Dean thinks.  Charles Beeson directed the episode written by Sera Gamble (#3T7509).