Short answers, pulled from the story.
Francis II died on the 5th of December 1560 in Orléans from an ear condition. Physicians have suggested the underlying cause may have been mastoiditis, meningitis, or otitis that progressed into an abscess. The royal surgeon Ambroise Paré had considered performing a trepanation before the king's death.
Francis II was married to Mary, Queen of Scots. They wed on the 24th of April 1558 in Notre Dame Cathedral in Paris, following a betrothal arranged under the Châtillon agreement of 1548. The marriage produced no children.
Real power during Francis II's reign was held by his wife's uncles from the House of Guise. Francis, Duke of Guise, commanded the army; his brother Charles, Cardinal of Lorraine, controlled finance, justice, and diplomacy. Catherine de' Medici, Francis's mother, agreed to this arrangement at the start of the reign.
The Amboise conspiracy was a plot led by the seigneur de la Renaudie to seize King Francis II and arrest or kill the Duke of Guise and the Cardinal of Lorraine. The plot was exposed on the 12th of February 1560 when the Duke of Guise's secretary arrived with a lawyer who revealed the plan. Many of the captured conspirators were subsequently executed and their bodies hung from the battlements of Amboise Castle.
The Treaty of Edinburgh, signed on the 6th of July 1560, ended French occupation of Scotland and required France to withdraw its troops from the country. It also required Francis II and Mary Stuart to stop displaying England's arms on their coat of arms. Francis II and Mary Stuart refused to ratify the treaty and challenged the authority of the Scottish parliament.
Francis II was succeeded by his younger brother Charles, who was ten years old at the time of Francis's death in December 1560. Catherine de' Medici was named Regent of France by the royal council on the 21st of December 1560. A third brother, Henry, later became king in turn after Charles.