The Sarah Jane Adventures - Season 1 Episode 10

Luke eventually escapes from the Slitheen but the bigger problem is Mr. Smith, who is trying to kill Sarah Jane and her neighbours. However, help comes from an unexpected quarter, K9, Doctor Who's old robot dog, who now lives with Sarah Jane,and who keeps Mr. Smith busy in combat while Alan prepares the virus that eventually shuts down Mr. Smith and returns him to being Sarah Jane's benevolent helper, whilst the Slitheen escape empty-handed.