The 2006 adaptation of the tale of Isolde the Irish princess falling in love with Tristan a British noble amongst all the warfare and politics of a post-Roman Britain. When Isolde is married to Tristan's adoptive father, King Marke can they resist their love for the sake of peace?
Of course not.
Tristan & Isolde - IMDb
Tristan & Isolde (film) - Wikipedia
A Summary and Analysis of the Tristan and Isolde Myth - Interesting Literature