Grace Bradley is now 99 years old. In the 20's, she served the Riverton Manor as a servant, and something bad happened. Robbie Hunter, a poet, killed himself, and now they're making a film about him, so her secret about that what really happened comes back up, and she decides to share it with her grandson Marcus by filming a tape of herself telling the secret.
She was a young girl when she was sent to work. The grandchildren of the house were David, Emmeline, and Hannah, and she meets them when they come to visit their grandparents. Hannah and Grace are quick friends, and Grace can't help but feel like Hannah knows something she doesn't. David brings his friend Robbie Hunter over one Christmas, and Emmeline loves him. David dies in WWI in the fulness of time. Robbie and Hannah reconnect, and Hannah is trapped in a bad marriage. They fall in love.
As for Emmeline, she grew into a dazzling woman in elite societies. She helps give Hannah and Robbie reasons to hang out. This is the famous poet, by the way. He served in the war and loves Hannah deeply, but she is taken. His post war trauma still lingers around in his daily life. Hannah is relocated back to Riverton. Hannah writes two letters, one to Grace, which she discovers but cannot read because it's shorthand, and one to Emmeline which Grace reads and discovers is a suicide note depicting Hannah's inevitable death by drowning.
Emmeline thought Robbie would be in love with her. After all, Hannah didn't even like him when they were kids. She pulls a gun and threatens to commit suicide. Hannah takes the gun. There are fireworks in the background that are triggering PTSD anxiety in Robbie who is slowly sliding into panic and confusion. Robbie decides that Emmeline must die. Emmeline rushes the gun at the same time, but Hannah lifts it and shoots Robbie. Emmeline decides to pretend it was a suicide, and the police believe her. She dies in a car accident.
Hannah is beside herself. Grace wants to know why Hannah wrote her letter in short hand, but Hannah doesn't say. She is pregnant. She dies from complications in childbirth, but the baby lives. Baby Florence goes to live with Hannah's aunt in America.
The shorthand letter is finally deciphered by Grace later in her life. It said that Hannah and Robbie were going to run away together, but she needs to fake her death to do so. Grace failed to deliver the letter that would have saved them all. She confesses this secret through the tape and dies with a clean conscience.
