I fabricated a trip to Toronto, so that I could watch my own home when everyone in it believed I was gone, and learn, at last, who was really doing what to whom.

I thought I was setting a trap for my housekeeper.

I had it exactly, precisely backward.

And yet the method, however wrongly aimed, was sound, and I have thought about why, because there is a genuine principle buried in it, underneath my misdirected suspicion.

The reason the hidden cameras revealed the truth was that they observed my household when it did not know it was being observed, and that, it turns out, is the only condition under which the truth of people’s character reliably appears.

When Chloe knew I was watching, she was flawless: warm to my daughters, gracious to Marisol, the very portrait of a loving stepmother-to-be.