Toothy rivals introduced in the opener, Shark Wars (2011), unite in the sequel to battle an army of shark invaders from the far end of the Big Blue.
Having learned that he’s not fat (or “big-cartilaged,” as he prefers to put it) but a supersized prehistoric Megalodon, young Gray is propelled into playing a leading role in repelling a disciplined force of shark troops from Indi, led by King Finnivus, a spoiled and vicious brat with visions of world conquest. Fortunately, Gray is being tutored in martial “Shar-kata” by Takiza, an ancient and bad-tempered betta (Siamese fighting fish). He also finds common purpose with other “shivers” (the basic shark communal unit—though more open-minded shivers admit other species too) and discovers unexpected allies who arrive (thanks to Takiza’s ability to span entire oceans with magical speed) in the nick of time to turn the tide of the climactic battle. When Gray cries, or pants with exhaustion, the overall anthropomorphic conceit wears thin, but Altbacker expends some effort concocting his undersea setting and fills out the finny cast with familiar martial-arts–style character types.
A sure draw for the Kung-Fu Panda crowd, high on body count but low on gory details, it doesn't take itself too seriously and is fully sequel-enabled. (Animal fantasy. 10-12)