Useless and the Mandala Trap

Ewen Euston has the worst nickname in town: Useless. But when every child in the district disappears into a swirling mandala on the school oval, he's the only one left to save them.
With an old Labrador as his guide and a reluctant teacher-turned-witch as his ally, Useless discovers the children have been kidnapped by intergalactic criminals and sold to strangers who want to keep them.
The gateway home won't stay open forever. If Useless fails, the children--and his twin sisters--will be lost in another world.
Packed with twists, danger, and unlikely courage, Useless and the Mandala Trap is an unforgettable adventure for readers 10+ who love brave underdogs and parallel-world escapades.