When summer arrives on Nebulon, Zack discovers that his best friend, Drake, is afraid to learn to swim and decides to teach him before they go on a trip to water-covered planet Araxie.

Although Halloween is not celebrated on the planet Nebulon, Zach, a boy from Earth, discovers that ghosts may be real.

The Nelsons are heading for a winter vacation on a great new planet with Zack's best friend, Drake, and the boys can't wait to dive into the winter games, but at the resort, Zack realizes there are a bunch of hurdles he wasn't prepared for.

"Zack is headed back to Earth for the first time since moving to Nebulon. He can't wait to see Bert and show his new friend, the former bully Seth Stevens, all around his old stomping grounds. When Zach's dog Luna escapes and goes missing, sightseeing plans take an unexpected turn. Will Zack find Luna before he has to head home to Nebulon?--

When a cosmic storm hits, stranding the Nelsons on their new home planet, Nebulon, Zack's hopes of a white Christmas in Vermont are dashed, but Nebulon provides a surprising alternative.

"Zack's twin sisters are best friends, but when the two get into an argument while visiting another planet, Zack finds himself stuck in the middle of a tricky twin situation"--

Will troublesome cabin mates ruin Zack's summer at space camp on the planet Sylvan?

On the planet Nebulon in 2120, Zack joins his school's Explorer's Club and visits Juno, a planet made of crystals, but he is less than thrilled when he is partnered with the class bully.