Mr. Robson and Justine collect an American teacher, Martha Jordan, from the airport. Mrs. Keele cuts up her credit card and throws away the pieces, but Anna Wright cunningly reassembles them.
Anna has fun with Mrs. Keele's credit card, Justine's good intentions come to nothing, and Jacko tells Becky about his mum's mental deterioration.
Mr. Robson's romantic aspirations have a momentary knock back at Martha's Thanksgiving dinner, Anna locks Mrs. Monroe in the toilets and Jacko sets an aim of taking his sick mum to the seaside.
It's Sunday, and there's a car boot sale, football trials and a drama workshop at school. Jacko sells some precious belongings, while Arnie and Sam discover a suspicious trade in animals.
Arnie and Sam's investigation into the animal sellers lead them into trouble, all the males of the drama workshop quit, and romance is in the air for Martha and Mr. Robson.
Jacko takes his mum to the sea and learns some family history, Mr. Robson almost destroys his romance with Martha, and Jessica and her old public school friends accidentally eavesdrop on the Head's marital strife.
Anna gets involved in the "Animal Man" business, word spreads about Martha and Mr. Robson, and a light-hearted drama session leads to a serious assault on Jessica.
Paula attacks Jessica because of the rumour that Joe groped her, while Mr. Robson and Martha interrogate the boys to get the culprit. During a confrontation with Anna Mrs. Keele keels over.
Mrs. Keele recovers from her heart attack in hospital, Dennis photocopies Mr Parrott's Maths test, and Jacko spends time with his mother, but gets kicked out of the band as a result.
The school choir is resurrected. Work starts on a school brochure with photos being taken of the school. Arnie, Sam and Anna borrow the camera to get a further clue about the animal smuggling.
The school inspectors give Mr. Robson a worrying time. Arnie, Sam and Anna make a journey to Hertford and discover Animal Man's farm, but Anna can't keep herself hidden when she sees a puppy about to be drowned.
Arnie, Sam and Anna defeat the animal trader. The girls perform their "Bits and Pieces" drama for Mrs. Monroe who decides it's too risqué for public performance.
Dennis and Dudley accidentally damage the stage equipment used for the girls' play, but Dennis's shoe leaves a tell-tale imprint behind. Justine takes an old friend to a party, but witnesses an attack on the way home.
The girls find a way around Mrs Monroe's ban, and perform their feminist drama piece in a park.
Sam can't find a reliable location for the computer tennis tournament, Dennis reveals that it was Brian who assaulted Jessica and Robyn and Julie's second babysitting evening is no better than the first.
Anna is forced to join the choir, and surprises everyone with her talent. A school trip to East Germany is planned. Babysitting lessons are given by the school secretary.
Year Seven put pressure on Mr. Parrott's rapidly failing voice to get him out of the choir. Justine and Maria secretly record Martha's singing and replay it to the music teacher so that she'll go to Germany with Mr. Robson.
The computer game tournament ends and Sam wins, but the winnings are confiscated by Mr. Robson. Maria spends the night with a bloke she met at a party and has a huge row with both her father and with Richard.
Grange Hill goes to Germany for the choir competition. A trip to a youth club becomes an unpleasant experience: Jodie faces right-wing youths who resent the intrusion of the English, and Jessica gets drunk on Schnapps.
Josh's war memorabilia threatens an explosive end to the Germany trip, Mrs. Monroe treats her class on her last day, Martha decides she can't quit the U.S., and Justine and Maria leave their school days behind.