ONCE IS HAPPENSTANCE. TWICE IS COINCIDENCE. THREE TIMES IS WORTH INVESTIGATING.

When Mother Dorothy’s godmother dies of a heart attack and leaves all her money to the convent, Sister Joan is uneasy.

While on visiting duty at the hospital, she makes some tacit enquiries. Things don’t seem quite right.

The nursing staff are always away from their posts at crucial times.

The surly young doctor seems very out of sorts.

Then a little girl goes missing.

Sister Joan knows there’s something truly sinister going on. She teams up with Detective Sergeant Mill, but can they get to the bottom of things before tragedy strikes?