|Minor Increase||Minor Utility Charm, +2 Linen|
In order to unlock this Tale you'll want to head to Komada Beach, which can be found Southwest of Saicho's Point, then help Masako fight off the Mongol's. After the area has been cleared, head onto the beach with Masako and then follow the trail of Adachi Banners whilst examining the bodies along the way.
After the short cutscene has come to a close, follow Masako down the right path and you'll enter another scene upon finding her sons.
Take back the Lighthouse
Once you've dealt with the Son's, jump on your horse and follow Masako to the Lighthouse.
Here you'll want to quickly take out the Mongol's guarding the area, then wait a couple seconds and take out the reinforcements. Finally, speak with Masako to complete the Tale.