In 2001, author and aspiring local politician Michael Peterson is charged with murder after the suspicious death of his wife Kathleen.

While working on his defense, Michael considers an opportunity to tell his story in a documentary. Then, after learning shocking information about her stepfather, Caitlin wrestles with doubts.

As the DA’s office attempts to solidify their case, shocking new details surface about Michael’s past that threaten to derail the defense.

After an unexpected homecoming, a critical discovery rocks the Peterson household. Michael’s fate hangs in the balance as the trial ends.

After navigating a possible retrial, a 73-year-old Michael confronts a life-changing decision. Meanwhile, Martha and Margaret each share long-buried truths, and Sophie comes to terms with a revelation.