The Siren’s Sister by R. M. Dilleen is a fantasy novel about the grand adventures of an unlikely heroine in Sylfavaron. It all began for Deandra after answering a phone call at her temp job. They came for her soon after, evil spirits from the other side, and forced her to flee through a mysterious portal to Sylfavaron. In time Deandra adapts to the strange world she warped into and befriends a few of the locals. As she spends more time there, she uncovers hard truths concerning her father. Her search for answers will test her resolve, and she may well lose what remains of her humanity for the burden of truth is weighty. Join Deandra and her companions on their grand quest through the treacherous yet beautiful world of Sylfavaron.

The Siren’s Sister started strongly and held my interest for most of its duration. I liked the way Deandra developed as a character throughout the book. She was naturally overwhelmed from the outset by the world in which she found herself, but grew as a person and fighter as she became more familiar with Sylfavaron. The plot is unusual and character dialogue serves as the main vehicle to propel it forward. R. M. Dilleen satisfied my curiosity regarding Sylfavaron while taking care to avoid the dreaded info dump. The pacing is great and breathes life into every scene, be it a light moment or a life-threatening situation, and the control over the pacing made for some interesting combat incidents. This is a great fantasy book and one that fans of the genre will appreciate for its originality and strong characters.

R.M. Dilleen's The Siren's Sister is a must-read in which Deandra explores a foreign world while unwittingly fulfilling an old prophecy. Deandra’s entire existence is turned upside down when she accepts a job substituting for someone who is on maternity leave and finds herself in a brand-new realm filled with secrets she had no idea existed. As Deandra advances, she learns more about her past and who she is meant to be. As she battles with invisible forces and adversaries she has never met, impossible imaginings become her new reality. Before meeting new people and deciding to follow her heart, all Deandra wanted to do was return to her former life, where she felt at ease. She must ultimately decide which fate to accept.

The Siren's Sister has excellent descriptive imagery subtly incorporated into the narrative, which increases the intrigue in the plot. During the action, I could empathize with Deandra and was also prompted to want to know more. The book has straightforward, simple sentences that are nevertheless detailed. I applaud R.M. Dilleen for her exceptional work as her fantasy tale has romance, mystery, and action, making it a well-balanced and enjoyable read. The book was expertly edited, which contributed significantly to the reading experience. I’d recommend the book to adults and teenagers who enjoy fantasies, but not for youngsters because it has a few gory scenes.