Hayate no Gotoku! - episode 21 - 18 Aug, 2007

Nagi decides to take Hayate to an amusement park in her own backyard. After they reached their destination, "Nagi Nagi Land", Hayate asked Nagi why is there an amusement park; she responded that Mikado gave it to her as a gift. However, Nagi is not tall enough for most of the rides since they have a minimum restriction of 140 centimeters. While Hayate is roaming through the haunted house, Robot Eight, who was defeated in episode 3, appears to get revenge. After Eight's plan fails, he flees, upgrades, and breaks into Nagi's mansion for another chance for revenge. In the end, Hayate and Tama defeat Eight, and Shiori Makimura of the M.H.E. Corporation comes over to fix him up. Eight started his new life, by living with Shiori nowadays. (Source: Wikipedia)