The April Fool's Apprentice by Tiffany Lim

Welcome to Avril’s Emporium, the greatest store on Earth and a cabinet of curiosities that just happens to be a portal between the human world and spirit realm. When Hannah stumbles across Avril’s Emporium, she discovers a secret that has been hidden for centuries. The shopkeeper, Avril, is the Spirit of April Fool’s Day and is part of an immortal race of guardian spirits that protects human festivals. Hannah becomes his apprentice and meets the Spirits who visit the shop — including Diya, Cupid, the Leprechaun and the Grim Reaper. When the Reaper discovers that Hannah is a human apprentice, he wreaks havoc on the Emporium. Can Hannah save the store with the help of the spirits of Deepavali and Valentine’s Day?