Mel and Mac are looking for an asteroid to show as a science project. It's hard to do science when they are fighting all the time as (younger) brother and (older) sister. When they are walking through the woods, they see something, but it doesn't turn out to be a rock or meteor. Mel sees footprints and pretty soon, they are taken to a strange and socially awkward grown man. Mel and Mac must work together to do the difficult task of keeping Moses away from trouble, as they try and get Moses to where he came from - something that is more difficult than they thought as he turns out to be from far, far away.