It has been a year since the Haddock twins have defeated Drago with their alpha dragons. Everything is back to normal, their mother Valka is home, they have found their little sister Bella and much to Hiccup's delight, his older sister Kari has seemed to be in love with the newest addition to their gang, Eret a former dragon trapper. But everything changes when Dagur comes to them for Kari who was promised to marry him when she turned 21. Upon agreement with her brother, Kari agrees to go and marry Dagur to see if he really has changed just like he claimed he has.