Chapter 1-16 Through the Trapdoor

• The final exams of the first year begin. They have been given special new quills for the exam, bewitched with an Anti-Cheating spell. Professor Flitwick has them make a pineapple tapdance across the desk, and Professor McGonagall has them turn a mouse into a snuffbox and Professor Snape has them make a Forgetfulness potion.
• Their last exam is History of Magic. Hermione complains she needn't have learned about the 1637 Werewolf Code of Conduct or the uprising of Elfric the Eager.
• Harry is worried about his hurting scar and restless, feeling he forgot something. Suddenly he remembers. he wants to ask Hagrid about the dragon-egg. They hurry over to Hagrid's hut and start questioning him about how, where and from who he got the egg. In the middle of the story Hagrid mentions that he told the stranger, from who he won the egg in a bar, that it's easy to calm Fluffy down by playing music.
• Hurrying to tell everything to Dumbledore they run into Professor McGonagall who tell's them Dumbledore was called to the Ministry of Magic and left.
• Harry decides that he has to get to the Stone first. He will go that night. Ron and Hermione tell him they will go with him. They wait until everybody has left the common room. Harry gets the Invisibility Cloak and his flute from his room. When he gets back to the common room, Neville tries to prevent them from going and breaking the school rules which would cost Gryffindor more house points. Hermione freezes him with a full Body-Bind spell ¤ Petrificus Totalus.
• They go to the forbidden room. The door is already open, meaning that Snape already got past Fluffy. They manage to get past Fluffy, the three-headed dog, playing music on the flute, and enter through the trap door. After a long fall they land on a bed of Devil's Snare, a plant. It is trying to entrap them. Hermione sends a jet of bluebell flames on the plant to make it let go.
• Next they come to a room with a locked door. Hermione tries an Alohomora charm but it does not work. They see what appears to be birds flying abound them and then realize that what they see are winged keys. Harry manages to catch the correct one and open the door.
• After the key-room, they need to get through a room with life-sized chess pieces. Here they must play real-time Wizard Chess. Ron has to sacrifice himself as a player in the game to get Harry and Hermione to the other side.
• Fluffy was Hagrids obstacle, the Devil's Snare was Professor Sprouts, The keys were Professor Flitwicks, the chess Professor McGonagalls, leaving Quirrell's and Snape's obstacles still to be tackled.
• Quirrell's turns out to have been a Troll blocking the way, but it already had been knocked out. Snape's obstacle to guard the Stone is a set of potions, coming with a riddle to define the working of them. Hermione unravels the logic, giving the potion that allows you to continue to Harry, and taking the potion that allows her to go back. Harry takes the potion and steps through the fire-portal to enter the next room.