The Convent's Secret - C J Archer

To find the one man who can fix the magic in Matt's watch, he and India are led to a convent where the nuns will do anything to keep their secrets private. Including murder? Matt and India must uncover the truth behind the disappearance of the mother superior and two babies given to her care many years ago. But sometimes, the truth is painful and its exposure can have deadly consequences.

With his magic watch slowing down, Matt needs all the help India and his friends can offer before time runs out. But his nemesis will do anything to bring about his downfall, including rock Matt's family with a scandal that can ruin them, and Matt and India's chance of happiness.