Stuck in 30 Days by Brandy Miles

Zack’s eyes abruptly shot open as a sharp pain erupted from his stomach. His whole body convulsed, buckling against the object that fell on him, and suddenly he was wide awake, not a trace of drowsiness in his mind.
“Good morning, brother!” an annoyingly cheerful voice sounded right on top of him. “Morning, morning, MORNING!!!”
Zack glared at his little sister, but she just smiled back at him cheekily, still sprawled across his stomach. She was humming to herself in obvious satisfaction, kicking her feet playfully in the air as she studied the giant world map Zack had tacked to the wall next to his bed. Or rather, pretended to study – Zack could see her watching him intently out of the corner of her eyes for a reaction.
This was what he got for not arcane locking the door and setting up a basic alarm perimeter around his bed.
“Get... Ohh wait.. Again ???"