Long-separated identical twins Ellie and Kat are practically strangers when they accidentally launch themselves into the past with their inventor mother's half-finished time machine. A truce is the only way to survive and find a way home. Not that 1970 Chicago is so bad. Their supercool young hippie grandma is there, plus a new friend who might be a genius, and 10-cent Snickers! But home is home. Seeking help at a university physics department, they end up exposing their tiny time machine to the greedy gaze of Professor Wilkes Lavin. When Lavin swipes the machine for his own schemes, Ellie and Kat resolve to think like scientists and do whatever it takes to get home. In tricky situations, escapes, and sometimes just for fun, the sisters make the most of their identical twinness. Ellie's acrobatics and aikido come in handy; Kat calls on her tech know-how and, to Ellie's surprise, hidden talents for singing and improv. If they aren't careful, they just might become friends!