Valente, Dominique. Starfell #1

"First published in Great Britain by HarperCollins Children's Books in 2019."

"Willow Moss's small magic has always seemed unremarkable. But when the most feared witch in the land of Starfell appears on the Moss family's doorstep looking for help, it's not Willow's talented sisters she seeks, it's Willow. Because Willow is a finder of lost things--and Moreg Vaine says that last Tuesday has gone missing. Willow and Moreg set out on a perilous journey across the wilds of Starfell, looking for what they've lost. If they don't discover what happened to the missing day, the repercussions could be devastating for the entire kingdom" --