Marvel's the Avengers(Book 1)

Kaitlyn Summers is a ten-year-old girl with special abilities. Abilities that could either destroy the universe or save it. When a mysterious figure known as Loki comes to Earth and gains access to the Tesseract, he threatens to kidnap Kaitlyn and use her powers to take over New York. Nick Fury, Director of the international peacekeeping agency known as S.H.I.E.L.D., finds himself in need of a team to protect Kaitlyn and save the universe.