ALA Booklist

Adventure, magic, and Arthurian legend combine in a roller-coaster ride of secrets and mythology. When Jax Aubrey's father is killed in a car accident, a mysterious stranger shows up claiming to be his guardian. Jax isn't thrilled; Riley Pendare never buys groceries, keeps to himself, and is full of secrets. Soon Jax discovers an eighth day day between Wednesday and Thursday, known as Grunsday at only descendants of Merlin, Arthur, and the Knights of the Round Table can pass through. Evangeline, a girl who only lives on Grunsdays, becomes the target of those hoping to destroy the normal seven-day week, and it's up to Jax and Riley to protect her. The adventure starts early and whizzes along at a brisk clip, with more about Jax's past and the legend of Grunsday unfolding as the novel continues. Perfect fodder for fans who adore mythology, legends, and series with more volumes yet to come.

Horn Book

Jax's discovery that he is a "Transitioner"--someone who involuntarily moves once a week between the timeline of the regular world and an alternate eight-day-week timeline--opens up a realm of secret powers, alliances, and responsibilities that stretch back to the days of King Arthur. Jax's confusion as he struggles to discern friend from foe is tangible in this original, complex adventure novel.

Kirkus Reviews

Thirteen-year-old Jax wakes to an empty world, believing that he is the sole survivor of some terrible event. However, his isolation ends after only one day when he wakes again to life as usual. Following the death of his father, Jax is sent to live with Riley Pendare, a tattooed 18-year-old who can barely care for himself. However, when Jax discovers that he is a Transitioner, a member of an elite group that has access to a hidden eighth day each week, Riley may be the only one with the answers. Arthurian legends come alive as Jax learns that the eighth day was created by Merlin and other magicians to contain the power-hungry Kin. Imprisoned within a single day each week, some of the Kin and their allies are seeking to destroy the spell even if it means the world will be torn apart in the process. Ancient magic pairs nicely with modern intrigue as Jax is forced to navigate his dangerous new reality. Complicated alliances, unclear motives and ruthless villains will keep the pages turning. Although the plot is familiar, the inclusion of Arthurian legend keeps it fresh. A promising start to a new trilogy. (Fantasy. 8-12)

School Library Journal

Gr 5-7 Jax Aubrey wakes up one day to discover he is a Transitioner; a person gifted with an extra 24-hour day between Wednesday and Thursday. His guardian, Riley, is also a Transitioner, and begins to slowly introduce Jax to a secret world of magic and adventure. Jax soon realizes it's not all fun and games. Not all Transitioners are who and what they appear to be, and Riley is tasked with guarding the girl next door, a prisoner who only exists in this magical Eighth Day. The girl, Evangeline, is the key to rival Transitioners' plans to use the extra day to destroy the normal world. Only Riley, Jax, and their allies can hope to stop them. The Eighth Day is an interesting concept, and Salerni makes it work by having Jax learn, along with the reader, to navigate this extra day that is both fascinating and extremely dangerous. The concept melds Arthurian legend into present day in much the same way that Rick Riordan uses Greek and Egyptian mythology, with characters being descendents of heroes long thought to be folklore and their place in this world sometimes dependent on that lineage. There are a few points where the action stalls slightly, but in general the writing is fast paced and exciting. The story lends itself to further adventures and readers will be excited to follow Jax and eager to see what happens next. Erik Knapp, Davis Library, Plano, TX

Voice of Youth Advocates (Thu Apr 28 00:00:00 CDT 2022)

Jax is an orphan without a clue that he is a Transitionersomeone with the ability to live in an eighth day between Wednesday and Thursday, called Grunsday. But this answers the question about why Jax is not living with relatives, instead being raised by eighteen-year-old Riley. So now that his powers have awakened after his thirteenth birthday and a tattoo is administered, he is .ready to understand who Evangeline is, a mysterious girl next door with a powerful lineage making her a threat and a tool to overthrow the seven-day world.What takes place in this fast-paced, magical adventure is the discovery of lineage to King Arthur and Merlin, and Jax's own talents and powers on his quest to stop the destruction while trying to save a girl. There is an unparalleled mix of evil villains, humor, and background that set this up for a likeable trilogy to be recommended for fans of Percy Jackson and Harry Potter. The characters are vivid, and Jax is the star. The quest is action-packed, and the world that Salerni builds is unique and engaging. This series is absolutely necessary for middle grades, with a cover and title that will not fail in drawing a following.Alicia Abdul.