'Ali keeps a diary with some very private comments on events. She records her own cheeky remarks to Mum and Dad and their consequences. One event she records is the mysterious disappearance of various socks. She suspects the Sock Thief. She constructs a Sock Thief Trap. Unfortunately Dad walks into it in the middle of the night. Ali sets another trap outside, but again it fails. Mum gives little credence to the Sock Thief theory. She is proven correct when she tidies Ali's room and discovers all the missing socks.
'The next day Ali's best T-shirt disappears. She suspects the T-shirt Thief...' (Publication Summary)