After leaving Hana Valley, Amaterasu will be back at Shinshu Field. Head towards the center of the field, where the area's Guardian Sapling is. Use Bloom to restore it and clear the Cursed zone, allowing Amaterasu to explore the area. Now, head to the high part of Shinshu Field, up on a series of ramps until Amaterasu is at the top of a hill overlooking Lake Harami. Head down to the torii of the gate and enter the Moon Shrine nearby. There, talk to Mika and his complaints, then exit the shrine, only for the day to quickly change to the evening and a demon from Mika's Wanted List to appear. Kill it, then cross its name off the list.