The internship program at the Time Museum is a little unusual. For one thing, kids as young as twelve get to apply for these prestigious summer jobs. And as for the applicant pool... well, these kids come from all over history. When Delia finds herself working at the Time Museum, the last thing she expects is to be sent on time-traveling adventures with an unlikely gang of kids from across the eons. From a cave-boy to a girl from the distant future, Delia's team represents nearly all of human history! They're going to need all their skills for the challenge they've got in store, defending the Time Museum itself!