Swashbuckling time-travel plus soap-opera relationships make for a page-turning start to a promised trilogy. The mysterious death of Ethan’s older sister when he was only four left his family a wreck: his mother hospitalized with depression, his father an emotional automaton, and Ethan subject to horrific nightmares. But for Ethan, his real life for the past 12 years has been with the Guardians of Time, in their eternal battle to prevent the Order of Chaos from disrupting the proper workings of history. After he’s assigned to train his schoolmate, Isabel, as his first Apprentice, an ancient prophecy gives the pair only a few short weeks to thwart Chaos’s top general in his assaults against the past, before the unfolding of an even more terrifying destiny. Protecting the time stream is hardly an innovative concept in fantastic fiction, but Curley pulls it off with panache. While the various historical periods are only perfunctorily limned, the ritualistic panoply of the Guard itself begs for further exploration. Cocky, loyal Ethan and self-confident Isabel are likable enough, but the real hook for teen readers will be their romantic entanglements. Isabel hides her lifelong crush on Ethan, as her older brother, once his best friend, seethes over Ethan’s attraction to his girlfriend; meanwhile, an unlikely character recognizes in the oblivious Isabel his own destined soulmate. Anguished heartbreak and suppressed longing are bound to continue to spice up the history-hopping sword-and-sorcery, making the sequels an ongoing guilty pleasure. (Fantasy. 12+)