14-year-old Oliver Cates inadvertently transports Albert Einstein into the present with his computer. Before going back, Einstein helps Oliver work through his anger so he can reconcile with his mother, whom the boy blames for his parents' divorce.

Oliver has no one with whom he can share his secret, so he summons Alexander Graham Bell. However, his secret is uncovered by a curious 14-year-old named Dee Sampson who, thanks to Bell’s advice, Oliver eventually befriends.

Dee is upset by her parents’ investment in a toxic pulp mill, so she summons Joan of Arc to help organize a protest, despite Oliver’s reservations.

Dee’s reticence to leave her childhood behind motivates her to summon writer Lewis Carroll, whose real name is Charles Dodgson, who helps her deal with her grandmother’s death.