The 47th episode of The Sarah Jane Adventures airs on CBBC, starring Elisabeth Sladen (Doctor Who). Tommy Knight returns in the season four finale. 
With Ruby’s true identity revealed, Sarah is trapped. Clyde and Rani aren’t convinced by the “message” Sarah leaves for them by way of Mr. Smith, however, and Ruby immediately sets about trying to turn the two against each other. But Ruby hasn’t counted on one thing – Luke returns from Cambridge, trying to find out why he can’t contact Sarah.
written by Clayton Hickman & Gareth Roberts
directed by Joss Agnew
music by Sam Watts / title music by Murray Gold
Cast: Elisabeth Sladen (Sarah Jane Smith), Tommy Knight (Luke Smith), Daniel Anthony (Clyde Langer), Anjli Mohindra (Rani Chandra), Alexander Armstrong (Mr. Smith), Mina Anwar (Gita Chandra), Ace Bhatti (Haresh Chandra), Julie Graham (Ruby White), Eddie Marsan (Mr. White), John Leeson (voice of K-9)
Notes: Luke makes his first appearance in person since part 2 of The Nightmare Man here, as does K-9.
LogBook entry by Earl Green