The Superhero's Origin by Lucas Flint

With a new power at his command, Kevin Jason (Bolt) goes to visit his grandparents, who he has never met before, in the hope that they might be able to help him better understand the source of his new power.

But it soon turns out that enemies from his grandparents' past have come back to get revenge for the crimes committed against them. Not only that, but Kevin's grandparents have a mysterious agenda of their own that seems to involve Kevin in a way he cannot understand, but must if he is going to survive.

Now Kevin must find out the truth of his grandparents and his family before their enemies catch them. And if Kevin fails, then this may spell the end of his family.