Mary returns to Scotland to assume her role as Queen. The country is deeply divided between Catholics and Protestants, with John Knox being a prominent Protestant leader.

Mary attempts to rule as a Catholic monarch in a predominantly Protestant country. She initially tolerates Protestantism, hoping to maintain peace and stability, but faces constant challenges from Knox and other Protestant lords.

Mary marries her cousin, Henry Stuart, Lord Darnley, a Catholic claimant to the English throne. This marriage is unpopular with many Scottish nobles, including her half-brother, James Stewart, Earl of Moray.

Mary's marriage to Darnley quickly deteriorates. He is arrogant, ambitious, and prone to violence. Mary becomes increasingly disillusioned with him.

A group of Scottish nobles, led by Darnley, murders David Rizzio, Mary's private secretary, in front of the Queen, who was heavily pregnant. They suspected Rizzio of undue influence over Mary.

Mary gives birth to a son, James, who secures the Stuart succession. His birth provides hope for future stability.

Darnley is murdered at Kirk o' Field in Edinburgh. The house he was staying in is destroyed by an explosion. Suspicion immediately falls on the Earl of Bothwell, and potentially Mary herself.

Mary marries James Hepburn, the Earl of Bothwell, who is widely suspected of murdering Darnley. This marriage is deeply unpopular and fuels rumors of Mary's involvement in Darnley's death.

Scottish nobles, opposed to Mary's marriage to Bothwell, confront her forces at the Battle of Carberry Hill. Mary surrenders and is imprisoned in Loch Leven Castle.

Under pressure from the Scottish lords, Mary is forced to abdicate the throne in favor of her infant son, James. Her half-brother, James Stewart, Earl of Moray, becomes Regent.