Diana is doing what she loves in France, using her rowing to combat her feelings after what happened in her chambers.
Philippe needed to be sure of Diana, but he didn't know Ysabeau trusted her and accepted her into the family. He's shocked to see it not because of what it means to Diana but him. Ysabeau would never have parted with that ring while he was alive.
Diana struggles with what it means that she wanted to kill a man.
Philippe writes a letter to Ysabeau, fingering his ring in 1590 while she does the same in the present.
Marthe is concerned about the witches, and she's right to be. Something is strange is happening.
Philippe's letter is arriving centuries later via a faint vibration that sends the women searching the library for what's changed.
Philippe can't get his mind around what he knows. Grabbing two swords, he plans on getting the truth out of Matthew one way or another.
Philippe cannot believe Matthew left Ysabeau alone to fight his enemies without protection for a witch! Where is his might? His thirst for blood?
While they do that, Diana discovers Ysabeau's map of covens to hunt. Diana gets to sleuth. Finding Ysabeau's map for witch hunts, she manipulates it, hopefully changing the course of the future.
Philippe and Matthew are tearing each other apart.
Diana comes upon Matthew deep in blood rage, but even then, he will not tell his father how he died. Philippe lovingly touches his son's forehead before parting.
Diana doesn't know how to help her beloved, who hasn't lost control like that in a very, very long time. He spills his guts. This is why they can never truly be mated.
Diana confronts Philippe, shows her true self, and he anoints her dead and alive again as a member of the de Clermont family.
Matthew tells Diana how Philippe died at the hands of the Nazis who used witches to extract his memories, torturing him to see how much pain he could endure before he died. It went on for three months. With Baldwin's help, Matthew rescued him. With a broken mind, Philippe begged Ysabeau to kill him, but he couldn't let her live with that, so he did it.
Most creatures unfurl like ribbons, but not Philippe's. He was broken and frightened, but in his final moments, all he thought of was Ysabeau. Ysabeau cannot look at him without remembering that day, but now he has to face her, too. Diana tells him he didn't kill Philippe; he released him.
In the present, they're still searching for what changed. Ysabeau can't let it go. She knows there's a message there. She will continue searching.
Philippe asks Diana about Ysabeau, wanting the truth she will give and not Matthew's glossed over version. Ysabeau is well but lonely, missing her husband.
He has taken Matthew and Diana to the temple of her namesake, where brides go for blessings. In two days, they will be married.
He gets hair, a symbol of her maidenhood and money, a symbol of her worth, and he asks for Diana to watch over Diana.
She places her items next to those of others, and a white stag shows itself. Artemis has accepted her gifts.
Matthew formally asks for Diana's hand in marriage.
Diana looks spectacular. Matthew can hardly stand to look at her.
Afterward, Philippe has the first dance with his daughter. More tears!
Diana wonders how they will keep this secret when Ysabeau returns. He has made plans, but he wishes that Ysabau was there to see Matthew's happiness.
Their wedding song is Time in a Bottle.
Their wedding night is everything they dreamed of.
Matthew is reminiscing about Lucas, looking at a carving he made for Lucas. Lucas gave him purpose, igniting a love he had never known. Diana is so sorry they won't have children of their own. She'd like to leave him with family. He'll live on without her for millennia.
It's time to say their goodbyes. Philippe is totally in love with his son's love for Diana. He ensures his son that he is equally worthy of Diana and asks that he stop regretting his life and start living it. He also forgives Matthew for anything that happens in the future.
Their parting finally gives Philippe the inspiration to write to Ysabeau and accept his fate. At the same time, she finds his letter centuries later.