"When seventh grader Nicholas V. Landrew, his beloved pet gerbil Henrietta, and a package of ground beef are beamed aboard an alien space ship, they soon find themselves on the run in a madcap chase across the universe. Now all Nicholas wants to do is get back home before his parents find out and ground him forever, but with the Universal Police hot on his trail, that won't be easy. Before it's all over, Henrietta will find herself safely ensconced...

When the class gerbil escapes from his cage, the children look everywhere for it and find a way to get it to return home

Obi the gerbil must fend for herself in a dangerous household, consisting of a dog, three cats, a parrot, and a mouse hidden in the attic, when the Armstrongs go on vacation and instructions for taking care of Obi get lost