The crime
Keith Raniere is currently a guest of the federal government in a sex-offender supermax prison in Tucson, AZ. Per a Wikipedia page that, thanks to a lifetime of shockingly successful hucksterism and intimate blackmail, is quite lengthy,

Raniere was found guilty of:

• Sexual exploitation of a child and possession of child pornography with regard to minor victim "Camila";

• Sex trafficking of "Nicole"; attempted sex trafficking of "Jay";

• Identity theft against Edgar Bronfman, James Loperfido, Ashana Chenoa, "Marianna", and Pam Cafritz;

• Trafficking for labor and services of "Daniela"; forced labor of "Nicole";

• Conspiracy to alter records for use in an official proceeding;

• Sex trafficking conspiracy, forced labor conspiracy, racketeering conspiracy, and wire fraud conspiracy.

tl;dr — he ran a sex cult.

The story
I didn’t realize a second installment of The Vow was on its way until HBO told me I had screener access. The first installment, which preoccupied us two years ago, felt very complete, perhaps even slightly overlong — and all the courtroom/criminal-justice “plot” Part 2 covers is information that’s a year old by now. Did we need another installment, this one “only” six episodes but most nearly an hour, and the finale nearly feature-length?