Academy City

T1 E1: Tōma Kamijō, a Level 0 student living in Academy City, has a unique esper ability that allows him to nullify psychic, magical and divine powers, but it also negates his own good luck. He survives a reluctant duel with said ability against Mikoto Misaka, a powerful Level 5 psychic capable of controlling and generating electricity, ending with Mikoto causing a citywide blackout. The next morning, Tōma wakes up to find a young nun from the Church of England hanging off his balcony. Introducing herself as Index, she reveals that she is being chased by magicians because she carries 103,000 grimoires. The two become friends after an embarrassing incident, involving Index proving the existence of magic and Tōma proving the power of his right hand, and they part ways. However, when he returns home from remedial class, Tōma finds Index laying on the ground bleeding and, behind him, a man who calls himself a magician.