Ultimate Spider-Man #5

Synopsis

LIFE LESSONS Harry Osborn is woken up by his mother's screams while a fire is burning down Osborn Mansion. Harry can't help his mother, who presumably dies, but he does see a monster throwing some fireballs and then leaving the place.  Peter arrives home to learn that his uncle has been shot by a burglar. As Spider-Man, he chases the burglar down to an abandoned warehouse, where he learns to his dismay that this is the same criminal he could have stopped before when he had the chance. At last he understands what his uncle had been trying to tell him, that with great power comes responsibility.