context: Richard Tyler is a geeky, timid kid who spouts statistics about the probability of accidents. His parents try to find 'normal' activities for him, to little avail. His father is slightly injured while building Rich's treehouse, further confirming Rich's phobias.As a storm hits the area while riding his bike home from the hardware store, Rich takes refuge in the town library. He meets the eccentric librarian, who tried to talk Rich into exploring the fictional area of the library. On his way to the payphone, Rich's curiosity leads him to the fantasy section, and, still dripping wet, slips on the floor and hits his head. When he awakens, the paintings of wizards and dragons in the library start to come alive. Rich is soon part of the paintings, having become 'illustrated'. Rich meets the wizard, known as "The Pagemaster". The Pagemaster tells Rich to get back home, he must face three tests: Adventure, Horror, and Fantasy.Rich first meets Adventure, a pirate book, who agrees to help him. He also meets Fantasy, a fairy tale, who also will help him if Rich helps them get 'checked' out as well. Unfortunately each time a book is opened, the characters come alive. A hound from Baskervilles chases them all into the Horror section, where they see the Exit sign beyond a haunted house.
  After some coaching, the three of them approach the house where they encounter Horror, who warns them of Dr. Jekyll and Mr. Hyde. He agrees to help them nagivate the house.Once inside the meet Dr. Jekyll, who transforms into the monstrous Mr. Hyde. He chases all the them throughout the house, where they encouter bats, ghosts, and gargoyles. Rich learns to escape and rescue his friends, getting braver with each hurdle. Eventually they escape the house, find a boat, and start sailing to the exit with Adventure as captain. Soon they see whaling ships, let by Captain Ahab hunting Moby Dick. The whale wrecks their boat, sending them all into the water where they become seperated. Rich and Adventure find a floating piece of wood, and soon a row boat with two unsavory characters comes to their rescue. Unfortunately they take both of them back to the pirate ship where they meet Long John Silver and are taken prisoner.Long John Silver lands on Treasure Island and finds the treasure chest empty. As a fight ensues, Fantasy and Horror show up to rescue Rich and Adventure from the pirates. Rich finds his courage to help send Long John Silver on his way. Free from the pirates, but marooned on the island, the group ponders what to do next. Adventure finds Rich's library card as they realize Horror has been captured by the Lilliputians. They rescue Horror as Fantasy realizes her wand is working again.The group starts toward the Exit, encountering many well-known characters from classic books along the way. Finally they reach the bottom of the mountain where the Exit is located on top. However the cave in the mountain is guarded by a fierce fire-breathing dragon. Rich and the books fight the dragon, Fantasy losing her wand in the process. They make their way to the top, chased all the way by the dragon. The books are trapped, and Rich goes back to save his friends. He fights the dragon, but the dragon swallows him whole. Rich finds Fantasy's wand and many books inside the dragon. Rich opens Jack and the Beanstalk, and the beanstalk immediately sprouts and grows, carrying Rich up and out of the dragon. Rich and the books get to the top of the mountain and the Exit.After walking through the Exit, Rich and the books meet the Pagemaster. Rich realizes how much he has learned and experienced on his journey, and the courage he has gained. The Pagemaster sends Rich back to the library, where he awakens. The librarian helps Rich up, and Rich checks out three books - Adventure, Fantasy, and Horror. Rich rides his bike home, a braver and changed boy. Rich's parents find him sleeping in his tree house, with his three books by his side.
question: when does the groups been separated?
answer: When monstrous chases all of them