When Heather and Wally's parents inform the two that they are expecting guests from out-of-town, they must hide Denver that the local movie theater, which is believed to be haunted.
Un niño genio, Freddy Facknitts, inventa una máquina del tiempo que envía Denver y Morton Fizzback en el pasado y en medio de una competencia de hombre de las cavernas loca llamada Mammothball.
