Alfie Wickers (Jack Whitehall) has taken Class Form K on a school trip to Amsterdam. Unbeknownst to him, Mitchell (Charlie Wernham) had spiked his Crepe with magic mushrooms, causing Alfie to hallucinate, thinking Jing was a panda and was convinced that the Anne Frank dummy was alive, causing him to steal it from the museum (parodying ET) and ends up in a canal.
One year later, the PTA led by Joe's mum, Susan Poulter, insists that Alfie gets sacked from the school, but Martin Wickers (Harry Enfield) Fraser (Mathew Horne) and Rosie (Sarah Solemani) insist that Alfie is given another chance and that they conduct a surprise visit to the class room. They are unaware that Mitchell tried to do a tattoo on Alfie's back labelled "CLASS K FOREVER" but only manages "CLA" instead. They burst into his classroom during a game of class wars, which ends with an unfortunate incident with Mrs. Poulter and the class hamster.
Alfie informs the children that they are going on a trip to Cornwall, and he reminisces on a trip to 'Shagaluf' with his teenage friends.