It is part of a series of books about a brother and sister duo who find aliens who are identical to them. Usually to get out of chores, they switch places with the aliens who aren't as familiar with the earthly rules and trouble happens.
Barton and Nancy are supposed to be minding the store -- the pet store, that is. But instead they're off trying to win tickets to see their favorite band, Woptic. So who's watching the animals? Their alien clones, Beta and Gamma, that's who! They can take care of a few little critters....What could go wrong?
