When an interesting old French oil painting goes missing from posh Les-Jen Lodge, home of one of my school mates, it creates a mega-drama for us Robinsons.  All the evidence points to my big sister Sarah being the person responsible - and unless Lindy and I can find out what's really happened, it could be the end of Sarah's days at college and her dreams of becoming an artist....

As told to ANNE DIGBY, bestselling author of the Trebizon boarding school series and the further adventures of the Naughtiest Girl.