Thirteen-year-old Michael Parsons is dealing with a lot. His father's sudden death; his mother's new husband, Glen, who he loathes; his two younger siblings, who he looks after more and more now that his mother works extra shifts.
And then one day, Michael wakes up and his mother is gone. In her place is an exact, duplicate mother. The 'other mother'. No one else seems to notice the real version is missing. His brother, his sister, and even Glen act as if everything's normal. But Michael knows in his heart that this mother is not his. And he begins to panic.
What follows is a big-hearted coming-of-age story of a boy struggling with an unusual disorder that poses unparalleled challenges - but also, as he discovers, offers him unique opportunities.