Short answers, pulled from the story.
The name Plantagenet derives from a bright yellow flowering plant known as genista, or common broom. Geoffrey, Count of Anjou, earned the nickname Plantegenest, or Plantagenet, likely for wearing a sprig of this bush in his cap.
Henry II became the first Plantagenet king of England in 1154. He inherited not just England, but also Normandy and Anjou through his marriage to Empress Matilda.
Four of Henry II's knights killed Archbishop Thomas Becket in Canterbury Cathedral on the 29th of December 1170. The murder occurred after Becket resisted a failed arrest attempt and had excommunicated those who had offended him.
The main Plantagenet line of kings ended when Richard III was killed in 1485 after an invasion by the forces of Henry Tudor. Henry assumed the throne as Henry VII, founding the Tudor dynasty and bringing the Plantagenet line of kings to an end.
The House of Plantagenet went extinct in the legitimate male line in 1499 when Warwick was executed. This execution followed the death of Richard de la Pole, who had claimed the kingship in his own right in 1513.
The only Plantagenet known to have died from the Black Death was Edward III's daughter Joan in Bordeaux. The Black Death brought a halt to Edward III's campaigns by killing perhaps a third of his subjects.