No matter who asks Sammy Keyes the question “What are you up to?” the answer’s always the same: trouble. While sneaking up the fire escape to Gram’s apartment in a seniors-only complex, where Sammy illicitly resides, she surprises an old man sneaking down. The encounter is apparently too much for the gent, as he suffers a heart attack and (after demanding that Sammy empty his pockets of greenbacks) kicks the bucket. To avoid jeopardizing her living arrangement, Sammy calls 911 from the apartment next door to Gram’s, which is occupied by elderly Mrs. Wedgewood. Then all hell breaks loose, and what seems to be a delicious monetary windfall for Sammy gives rise to both a mystery and a moral quandary. Adding zest and teen interest to the quirky puzzle, whose geriatric backdrop initially seems an odd venue for young readers, are generous helpings of raucous comedy (most involving rotund Mrs. W.’s inability to stay upright on her toilet), a wonderfully cheeky first-person narrative, and smoothly integrated interactions between Sammy and her age mates. The result is an exceptionally good entry in an already remarkable series.