Thanks to the arrival of the mysterious Italian “exchange student” Dante in her life, Abby Edmunds has broken out of some stale patterns: she is no longer dating the sweet but predictable guy she has known practically her whole life; she is ready to “live without limits” at a small liberal-arts college far away from her family and friends — and she may very well be about to witness the unraveling of time.

Dante’s 500-year-old cohorts have just gone through the door again, and this crossing will not just affect them, but all of humanity, because the villain Zo is up to no good. He starts messing with Abby’s timeline, causing her at first just some consternation, but then as more happens, absolute fear and heartache. Abby has no idea how she can possibly fix things — and Dante is stuck somewhere, unable to help, with his own future looking dim. As Abby’s life keeps changing, and her support system is being picked apart by Zo, she must turn to some unlikely sources for help.

Second novels in trilogies tend to be the most frustrating to read; the action gets more intense and problems much stickier, and little is resolved by the end. The reader must simply wait for resolution from a third book. When a third book isn’t published yet, that wait is a touch agonizing. If fans of The Hourglass Door, the first in Mangum’s series, read this new one right away, they will just have to take comfort in knowing that the third book is planned for publication a year after The Golden Spiral. Good luck to all of you who will be holding your breath for a while!

Rated: Mild, for some violence, and one character saying once, “go to h-.”