Cynical teen Dash and his optimistic friend Lily start trading daring dreams and adventures in a notebook they pass between each other across various locations throughout New York City. As their adventures become more and more daring, they find they have more in common with each other than either expected.
When Texas cop and former Navy SEAL Martin Riggs suffers the loss of his wife and baby, he moves to Los Angeles to start anew. There, he gets partnered with LAPD detective Roger Murtaugh, who, having recently suffered a "minor" heart attack, must avoid any stress in his life.