Original title (JP): ベイビーわるきゅーれ ナイスデイズ (Beibī waruki ~yu ̄ re - naisudeizu, Baby Warukyuure - Nice Days)

Teenage assassins Mahiro and Chisato visit the coastal city of Miyazaki for a contract and a vacation when they unexpectedly cross paths with a legendary, bloodthirsty assassin who's looking to add to his kill count.

https://www.themoviedb.org/movie/1279752