Traces in sugar

Gemma is looking forward to the May Day celebrations in Oxford, but the spring morning ends in murder. A conversation she accidentally overhears could be the key to the whole case. Four inquisitive old ladies offer to help her solve it! And so Gemma gets involved in tailing a 'princess', takes a Krav Maga course with the seniors, and tries to discipline her cat, Muesli, who is running riot in the local retirement home. But what's bothering Gemma most is her boyfriend's strange behaviour. Is he lying to her? And why? Will she solve this mystery before the banoffee pie gets cold?