All The World’s A Stage by Boris Akunin
Eliza Altairsky-Lointaine is the toast of Moscow society, a beautiful actress in an infamous theatre troupe. Her love life is as colourful as the parts she plays. She is the estranged wife of a descendant of Genghis Khan.
And her ex-husband has threatened to kill anyone who courts her.He appears to be making good on his promise.Fandorin is contacted by concerned friend - the widowed wife of Chekhov - who asks him to investigate an alarming incident involving Eliza. But when he watches Eliza on stage for the first time, he falls desperately in love . .
. Can he solve the case - and win over Eliza - without attracting the attentions of the murderer he is trying to find?