Brian and Sophie decide they need to make a new friend – and with the children starting school, a teacher seems the perfect choice.

Sophie's involvement with an international crime ring puts the family under threat, while Brian believes a visiting exchange student is a fellow extra-terrestrial.

Sophie and Brian try to act like normal human beings – though unfortunately he opts to be the model wife while she wears the trousers. Brian is being operated on by Becky and the family. Becky needs to get some of Brian's insides in order to stop the mutated flu virus melting him.

Brian discovers a treasure chest, and sets out on a mission to splash the cash. Meanwhile, Sophie confronts a teacher that has insulted aliens, and Eddie breaks his friend's new computer.

Sophie rescues Jaq from a surfing accident, and soaks up the praise that accompanies her heroics. However, to regain the warm feeling it gives her, she engineers more and more dangerous trials for the youngster to face in order to save the day once more.

Brian and Sophie find a huge Christmas tree. Without knowing how much energy it uses up, it threatens to blow up the spaceship. Eddie gets his confiscated Christmas present back and Jaq comes back home. Dan, Becky, Eddie and Jaq need to de-frost Brian and Sophie. After de-frosting them the meltdown only has 30 seconds left. Sophie's too frightened to press one of the four buttons and with three seconds left will the spaceship blow up or not? At the last second someone presses a button, but who is it and is it the wrong button??