The phone call that sounds exactly like your granddaughter

It comes in the early evening. The voice is crying, so it's hard to hear clearly — but it's her. There's been an accident, or an arrest, and she's not supposed to be calling. Please don't tell Mom. Then someone else takes the phone: a lawyer, a bail bondsman, an officer. They need money today, and they'll explain how.

Every part of that script is doing a job. The crying covers the imperfections in a cloned voice. Don't tell Mom isolates you from the one person who'd check. The stranger on the line supplies authority. And “today” removes the twenty minutes of thinking that would end the whole thing.

The voice being right proves nothing any more. A few seconds of audio — a birthday video, a graduation post, a voicemail greeting — is enough to clone someone convincingly. Assume the voice will be perfect. It's no longer the thing you check.

What to do, in this order

1. Hang up. You are allowed to hang up on your own grandchild. If it's really her, she will forgive you in about four minutes.
2. Call her back on the number you already have. Not a number they gave you. The one in your phone.
3. Tell one other person. The secrecy is not part of the emergency. It's part of the scam.

The thing that actually works, and takes two minutes

Agree on a word with your family. Not a birthday, not a pet — something no one could find online and no one would guess. If a caller can't say it, it isn't them, however much they sound like it.

Print it and put it by the phone.