Outnumbered by the children, head teacher Hilary Head calls for backup from some very unusual supply teachers, and a bromance blossoms for Mr Capp.

There's a dog poo-traipsing intruder in the school and site manager Dave is determined to catch the culprit. Meanwhile, Mr Nasal attempts to keep his relationship with Miss Spray a secret, and Mr Konnundrum's in trouble... with his mum.