The Creakers by Tom Fletcher.
The Creakers (2017) by Tom Fletcher is a funny, imaginative adventure about what happens when all the adults in a town disappear overnight.
Lucy Dungston wakes up one morning to find that her mum — and all the adults in the town of Whiffington — have vanished. Only the children remain. Lucy discovers that the adults have been taken by the Creakers — strange, smelly creatures who live beneath beds and in dark places. The Creakers emerge at night through The Woleb (the shadow world beneath our world) and have been stealing adults.
Lucy, along with her friend Norman and others, must travel into The Woleb to find the adults and bring them back. The Woleb is a dark mirror world full of Creakers and dangers. Lucy discovers that the Creakers are not simply evil — they have their own reasons for taking the adults.
The children rescue the adults and return them to Whiffington. Lucy gains a deeper understanding of her relationship with her mum, which was strained before the adventure began.