Horrid Henry's Sleepover is an episode in Series 1.
Henry gets more than he bargained for when he agrees to a sleepover at New Nick's house.
- Greedy Graham's voice sounds exactly like Henry's in a flashback.
- In a flashback, Moody Margaret's mum says "Come and pick up your son", despite living next door. Plus he was never seen at Margret's house and instead, he was at Greedy Graham's house.
- When Henry and Nick were watching TV, they were watching Rapper Zapper, however, its lines were very identical to Mutant Max's. Henry also said that Rapper Zapper told the aliens to die, even though the line was totally different.