When Arty's family announces they're moving to Las Vegas, the city's blazing lights threaten to put an end to Arty's stargazing dreams forever. Then Arty finds out he has to stay with his scary neighbor while his parents look for a house. As it turns out, "Mr. Death" isn't terrifying at all; he's actually Cash Maddox, a bona fide astronaut! When Cash falls ill, will Arty find the courage to complete his mission alone? And might he actually prove, once and for all, that there is life on Mars?