When Mel skips school to visit her mother's grave (she won't explain why at first) her teacher Mr Coleman decides it's time to pay a home a visit. Meanwhile, Brian has developed an allergy that causes him to sneeze and morph uncontrollably. Mel starts training Sophie to behave like a 'real' mother, while Lucy attempts to diagnose Brian's allergy. Unfortunately, during his visit Mr Coleman sees Brian sprout a new nose and ears, and resolves to return with their social worker. Josh is determined to hold a party to improve his social standing – could this somehow save the whole family from being taken back into care? Will the world find out Brian and Sophie are aliens?

Brian decides that he and everyone else should become a proper family so Brian enters a quiz night, however Lucy doesn't want to join so she goes to join Wendy's team and ends up playing against her family who will win and what will happen?

Mel arrives home late and expects to be grounded by Brian and Sophie but isn't. She keeps trying to get into trouble until she comes home with a walkman she says she stole. Josh tries to get a date with Tanya Thomas (Zoe Thorne), so he enlists Brian's help. Brian morphs into Josh and asks out Tanya's friend, Denise, who fancies him. When the two girls meet each other on the day of the date, they both start hating Josh.

Lucy finds an injured dog, which she names Dennis, and starts nursing it back to health. Mel disapproves, warning Brian that Lucy will be upset when it dies. Meanwhile, Josh spends the money he raised for a charity event on a football ticket, and starts to earn the money back by putting up 'dog found' posters for Mel. When Lucy finds out, she pays him even more to bring them all back again, by which time Mel has warmed to Dennis and agrees to keep him. However, Josh returns with a 'Have you seen Woolly?' poster and Lucy and Mel realize that Dennis, a.k.a. Woolly, needs to go home to the people who are missing him.

When Lucy calls Brian and Sophie "Mum and Dad", Mel gets angry and shows Lucy and Josh a box of things she kept to remind her of their real parents. However, a lipstick is missing from the box. Lucy realizes that it was she who had taken it and swapped it, so she must ask Josh for help. Meanwhile, after a string of Fs, Josh must resit his exams or be put back a year. To pay him back for helping with the lipstick, Lucy helps him revise, and discovers that he may be dyslexic.

Lucy discovers she and her best friend are 'geeks' after they are the only two girls in the class not to be invited to a party. Mel gives Lucy a makeover, but this threatens to alienate her from Wendy, with whom she has been studying caterpillars. Sophie is struck down with a case of the flu, but enjoys her freedom from housework and responsibility and hides her recovery. Lucy decides friendship is more important than being 'cool', and she and Wendy discover that their caterpillars "were really butterflies all along."

When Lucy wins tickets to see Blink 182 in a competition, Josh is desperate to take them off her hands – after all, he's a huge fan of the band, and Lucy's such a geek she's never even heard of Blink 182. Lucy agrees to give the tickets to Josh, but on one condition: Josh has to perform a truly unselfish deed in order to qualify for the tickets. Of course it's a terrible struggle for the scam-meister, but Josh learns a whole lot about himself in the process. Elsewhere Mel is upset (though refuses to show it) when Trent appears to be going on a date with another girl. The confusion is resolved later in the episode when it turns out that Kelly is Trent's cousin, not his date and he and Mel become friends again.

Josh injures himself during sports, so Brian attempts to fix him with a home-made machine. However, the machine instead makes Josh a chess champion and a maths prodigy by mistake, making Lucy feel threatened as she is outplayed in chess.

Josh wants to have a wild party for his class (including resident tough-guy, Big Verne) so he tries to make the rest of the family go on a holiday. Mel is aggravated by her family's constant need for attention when all she wants some privacy to write a song to enter into a competition with Trent.

Lucy and Wendy are on the verge of falling out, as Wendy is upset that Lucy never invites her to her house. They arrange a sleepover, and Sophie and Brian must act as normal as possible. Meanwhile, Josh is charging Sophie for doing chores around the house so that he can later buy a snooker table.

Lucy is selected to represent the school in a Science Tournament where she has to build a rocket with maximum propulsion – which proves to be too difficult a task for her, so Sophie offers to help. Brian enters one of Mel's photograph's in an art contest. Josh tries to bribe Scott Taylor into letting him join the football team and get to go to Holland and almost loses Frankie and Pete as friends.

Mel goes to school in trousers, as she feels the school rule that girls must wear skirts is sexist, whilst Lucy is looking after the school hamster which Josh promptly loses by trying to make some money with it.

Lucy manages to get her way in the house, organising chess nights and debates. Due to this, Josh gets the idea to run for school council. He claims if appointed, he would get all students entry to the prefect's room, much to the anger of Mel. Mel has a secret weapon – if he continues in his plan, she will blackmail him with a karaoke tape of him singing along to Britney Spears. But then when she puts it on in the school Josh starts to sing and everyone gets dancing so Mel gets annoyed and leaves with a sulk.

Lucy's birthday is arriving, and she wants a party. While she thinks no-one is interested, the family is planning a secret party. When Sophie becomes pregnant, Josh is elected to give Brian 'The Talk' on the facts of life, with help from a book from the school library. However, Brian later becomes pregnant as well. Lucy plans a party with Wendy, will her friends come over, before Brian and Sophie's babies are born? And how will Lucy's party go?

Mel asks Scott Taylor to the school Christmas disco, causing Trent to get jealous. Lucy is cast as Mary in the Nativity play, a part Wendy wants. Josh fills Brian and Sophie in about Christmas. Lucy gives Wendy the part of Mary in the play, but Wendy becomes extremely demanding. Mel gets cold feet and won't go to the disco, so Brian morphs into her and goes in her place. Mel finds out and rushes to the disco, only to find Brian-Mel kissing Scott, right in front of a heart-broken Trent! Mel attempts to repair the damage caused by Brian, only to find out some things about herself. The school Nativity play becomes a strain on Lucy and Wendy's friendship. Josh has nightmares and is visited by ghosts in a plotline similar to that of Dickens A Christmas Carol.

Mel asks Scott Taylor to the school Christmas disco, causing Trent to get jealous. Lucy is cast as Mary in the Nativity play, a part Wendy wants. Josh fills Brian and Sophie in about Christmas. Lucy gives Wendy the part of Mary in the play, but Wendy becomes extremely demanding. Mel gets cold feet and won't go to the disco, so Brian morphs into her and goes in her place. Mel finds out and rushes to the disco, only to find Brian-Mel kissing Scott, right in front of a heart-broken Trent! Mel attempts to repair the damage caused by Brian, only to find out some things about herself. The school Nativity play becomes a strain on Lucy and Wendy's friendship. Josh has nightmares and is visited by ghosts in a plotline similar to that of Dickens A Christmas Carol.