Original: When he is sorted into Gryffindor House, he becomes fast friends with classmates Ron Weasley and Hermione Granger, and foils Voldemort's attempt to steal the Philosopher's Stone.
Simplified: He is sorted into Gryffindor House by the Sorting Hat and becomes friends with classmates Ron Weasley and Hermione Granger. Near the end of his first year at Hogwarts, he stops Voldemort's attempt to steal the Philosopher's Stone.