The Musketeers escort the royal court to see the astronomer Marmion and his display of the solar eclipse.
When they arrive, members of the Red Guard are quickly murdered by Marmion's servants.
Back at the barracks, Athos, who has elected not to attend the eclipse due to Milady's presence, and Treville discuss his recent demotion from Captain.
At the moment of the eclipse, Marmion's men take the King and Queen hostage. Aramis begs him to have compassion and let the women and the baby go, but Marmion pushes him out of a window for speaking up.
Marmion proposes a game of chance; call the coin toss correctly and you leave, wrong and you die. Milady is the only one brave enough to take the chance, and she wins her freedom.
Aramis, not dead from his fall, sneaks back into the fort and rescues the Queen, the Dauphin, and Marguerite.
Robert, Marmion's brother, has reservations about the kidnapping, when Marmion makes the King choose between killing his wife and child and three innocent courtiers.
Milady rides for the barracks and rallies the Musketeers to rescue the King.
Marmion reveals that his village fell to the plague and the King blockaded them inside to prevent its spread. It was their lack of food that killed them instead of the plague.
The Musketeers arrive and escort the Queen and her baby out of the fort.
Back with the King, Marmion makes him call a coin toss to free or kill Constance. When he chooses wrong, D'Artagnan steps in to be killer in her place. At the last second, Robert steps in front of the shot to spare his life.
The Musketeers stage a rescue with Rochefort and Milady. The King rewards Rochefort, and ends his relationship with Milady for deserting him.
Constance and D'Artagnan share a passionate kiss and decide to be together, no matter what society thinks.