SARA and TOM JOHNSON are two very bored teenagers. But that's all about to change. During a family vacation to an old western ghost town, the bickering siblings stumble upon a portal which catapults them back in time to the Old West. As if that wasn't odd enough, they meet a friendly baby alien whose ship has just crash landed in this prairie of the past. The creature's mother has been captured by some greedy locals and can only survive for a few hours in the Earth's atmosphere. The kids must somehow find a way to help the scared space visitor and his mom escape the planet before time runs out – and they're transported back to the future.