Stuart Gibbs

In this New York Times bestselling novel the moon base commander has gone missing and Dash Gibson is on the case. The second mind-boggling mystery of the Moon Base Alpha series from beloved author Stuart Gibbs.
There's nowhere to hide on the world's first moon base. After all, it's only the size of a soccer field. So when Nina Stack, the commander of Moon Base Alpha, mysteriously vanishes, the Moonies are at a total loss.

Though...

Have you ever felt like you didn't quite fit in? Bruce Wayne knows all about that...being the only kid in his whole school without any powers and all. And when he gets pulled into the principal's office because his career choice of vigilantism is deemed too ambitious, Bruce becomes more determined than ever to prove that he can be just as cool as the other supers that give him a hard time. But first, he has to find the right disguise and gadgets...oh,...

"Superspy middle schooler Ben Ripley races against time and across state lines - traveling by car, train, boat and plane - to track Murray Hill down before Ben's cyber enemies can find him"--

In 2041 on Moon Base Alpha, thirteen-year-old Dash must solve the mystery of how Lars was poisoned before the base loses oxygen, forcing the colonists to return to Earth.

Tim and his friends travel by land and sea, collecting treasure and defeating monsters as they go.

"When Greg and the Musketeers return to Paris and find the city under siege, they leap into action to prevent King Louis from being overthrown and history from being changed forever"--

While visiting his girlfriend Summer in Malibu, Teddy stumbles upon two mysteries involving a blown up whale explosion and a string of beach sand thefts, but his investigation is sidetracked by a rumor that his girlfriend is dating a celebrity, leading him to question their relationship.

Greg Rich is getting the hang of things in 1615 Paris after assuming the identity of D'Artagnan and uniting the three musketeers. The boys are after Dinicoeur who escaped from the Bastille.

With no knightly experience but plenty of pluck and an impressive vocabulary, a twelve-year-old peasant, hoping to improve his station in life, volunteers to help a cowardly prince and his not very powerful wizard rescue a princess from an evil, foul-smelling monster.

Thirteen-year-old Ben Ripley is assigned to protect the president from an assassination attempt in his first solo mission, but he may be in over his head.