Twelve-year-old Cruz Coronado's adventures as part of a group of student explorers continues in book two of the Explorer Academy series (The Nebula Secret, 2018). They find themselves traveling by ship, leaving Maryland to traverse through Nova Scotia, Iceland, and Norway's Svalbard Global Seed Vault. In Canada's Bay of Fundy, they rescue North Atlantic right whales entangled in fishing netting. Cruz communicates with the whales using a UCC (Universal Cetacean Communicator) that the female tech-lab chief developed. Cruz, who received a threatening anonymous note from someone on board, isn't totally surprised when someone tampers with the UCC helmet and he almost dies. He suspects pharmaceutical company Nebula is responsible: both he and Nebula are after marble fragments, left by Cruz's deceased mother, which contain a formula that Nebula will do anything en kill obtain. This exciting, fast-paced, far-flung story is full of science facts and James Bond like gadgets, accompanied by colorful illustrations. The ending is guaranteed to keep readers eager for the next series installment.

Cruz Coronado is still feeling on edge after the attack on his life in series opener The Nebula Secret (2018) as the Explorer Academy sets off on the research vessel Orion for the next phase of its educational journey. Before Cruz's scientist mother's mysterious death, she hid the clues to a secret formula with world-changing healing potential in a holo-journal. Cruz and his academy friend and roommate, Emmett Lu, keep the secret of the journal close even as they discover that someone aboard the Orion is trying to steal it. Lani Kealoha, Cruz's childhood friend, video-calls Cruz and crew regularly from Hawaii, using her decoding skills to help decipher the journal's holographic clues. While dodging his assassins, Cruz pursues his studies, leading Team Cousteau to Norway, where the author infuses cool, scientific facts about the endangered North Atlantic right whale and the Svalbard Global Seed Vault into the narrative. The educational component of this story takes readers outside of the book via a link to an interactive companion website. Like its predecessor, this book is chock-full of National Geographic adventure interlaced with techno-future gadgets the academy provides its diverse young students (cued by naming convention). However, the author basically follows the same storyline rubric as the first book, so if readers aren't hooked by the science, there's little else for them. A formulaic second installment that takes readers around the globe but doesn't push the story forward. (Science fiction. 10-14)