Horrid Henry's Secret Surprise is the thirteenth episode of Series 2.
Mum, Dad and Peter are being very secretive - could they have something very special planned? Henry certainly thinks so!
Mum, Dad and Perfect Peter won't let Horrid Henry know about what's going on in his house. They make presents, get snacks and plan for a party, which Henry thinks is for him, so he invites his own friends. In the end, Henry sees the party is for Great Aunt Greta.