Our amatuer sleuth is a nurse at a Cambridge college and one of her boarders is commissioned to write a biography of a dead mathematician.
What she finds is that three previous people have been given the same commission, two are dead and one missing.
This is a bit silly, our sleuth, Imogen Quy is one of detective fictions folk who is never wrong, knowns more than all the experts, this while doling out aspirins to hung over students in her day job.
Paton Walsh writes a good crime book usually, she has completed the unfinished Wimsey book that Dorothy L. Sayers did not finish before her death and has written a couple more Wimsey's which are fun.
This however, is not that flash, trying to be Miss Marple without a decent story (the Cambridge College she is employed by is St Agatha's).