Hiccup is learning how to board a boat. He is supposed to find a peaceful fishing boat but instead he finds a Roman ship. Toothless rescues them but gets trapped on the ship. Hiccup then has a mission to rescue Toothless. Instead, Hiccup gets kidnapped and sent to Fort Sinister where Toothless is being held. Canzi, the heir of the Bog Burglars (Hiccup is the heir of the Hooligans). Then Alvin the Treacherous makes them fight shark worms but fortunately, Hiccup gets helped by Teeny Dragons and escapes.