On its surface, Jennifer Hillier’s Jar of Hearts is a thriller about a killer and those affected by his actions. However, the novel, which takes place on two different timelines, is a multilayered marvel that also explores the nature of interrupted love, looks at the result of trauma and dangerous traits that are carried in DNA, and shows the lasting impact a brutal murder can have on everyone involved in it. Furthermore, Hillier manages to pull off this plethora of elements while also entertaining with a carefully crafted, suspenseful narrative and by delivering a level of viciousness that will appeal to fans of hardcore horror fiction.