A 11-year-old Lacy, her mother Janet, three people who come into their lives over one summer in 1991

纪念英国威尔士王妃戴安娜逝世20周年，威廉与哈里王子第一次在荧幕上谈及母亲，全片回顾了戴安娜王妃的生平，她从事的慈善活动，巨大的社会影响力，以及震惊世界的死亡。