The second book in the 90s teen version of Tom Swift involves the titular character punching a hole through to another universe via a black hole where his life is radically different. He changes places with an evil version of himself, and while he navigates his alter-ego's dark world, his evil counterpart plots to take over his own world.
I loved this classic sci-fi mirror universe idea played out with Tom Swift, but this book suffers from too much cliche. Everyone in the dark universe has pony tails and greasy hair, and the evil swift is too obviously evil in the good universe. How no one notices is a major mystery throughout most of the book. Also, the book spent far too much time in the evil universe with the good Tom Swift. I would have liked to see equal time, and to see evil Tom Swift being thrown by being completely out of his element just as good Tom Swift was.
Also, the endgame of the book, both Swifts recreating their initial experiments, seemed very implausible, given that evil Tom Swift was doing so only to kill his good universe family and there must have been an easier way to do it.
Teen fiction or not, this could have been a bit better.