39 - The Joys Of Camping
Calum and Tom go camping for the weekend.
It is 10pm by the time they finish pitching their tent.
Tom gets into his sleeping bag and falls straight to sleep, but Calum tosses and turns, unable to get to sleep even though he is very tired.
At midnight, a noisy creature passes their tent and wakes Tom up – and Calum immediately falls asleep.
Why is this?