It's foolishness on the Pyramid Express and a tour of the Tomb of Doom. Bumbling adventurer Mr. Penguin (an actual penguin) and his band of assistants, Colin (a kung-fu spider who communicates via writing on his notepad), Edith Hedge (human BFF), and Gordon (Edith's omnivorous pigeon) return for a fourth spine-tingling, rib-tickling mystery adventure. Ostensibly arriving in the Egyptian desert town of Laghaz for a rest, Edith sets off with Gordon for a tour--but doesn't return. When Cynthia, her unexpected (to Mr. Penguin and Colin, at least) twin sister, shows up, the group discovers Edith has been kidnapped from the local library. Gordon has a clue to her whereabouts…but, of course, he has attempted to eat it. They hop on a train full of possible suspects headed for Wadi al Khatar, the Valley of Peril. The excitable Mr. Penguin has several freakouts about mummies and bandits until one of his fears actually pans out, and he and Colin find themselves tossed from the train. Thankfully, a young fan of Mr. Penguin's previous…um detective successes, a boy named Farooq, along with Iris, his eye-patch--wearing cat, have been following the group. They rescue the adventurers and get them to the valley, which, it turns out, is aptly named. Fans of the series will enjoy this twisty mystery with enough laughs and lively illustrations (containing subtle clues) to keep pages turning to the silly close. Delightful slapstick sleuthery. (Adventure. 6-11) Copyright (c) Kirkus Reviews, used with permission.