Sister Pelagia and the Black Monk (2008)

In Sister Pelagia and the Black Monk, Sister Pelagia of Zavolzhsk, a freckled, gawky nun, remains hopeless at womanly tasks but again proves an able detective. This time, Bishop Mitrofanii refuses to dispatch her to the monastery of New Ararat, where the ghost of the Black Monk has gone on a murderous rampage. Women, the bishop says, are not allowed at the holy site. But when Mitrofanii's emissaries fall prey to the Black Monk, the enterprising sister goes undercover as a skinny, redheaded monk to solve the crimes. Boris Akunin's mystery, steeped in Russian lore, goes down like a bracing cup of strong black tea. B+