Fushichougoroshi

Asuka Miyamoto was working as an insurance salesperson in Tokyo when her grandfather Shigeru warned her that something was amiss at their family shrine. Her brother Souichi, who had taken over the shrine, has gone missing and a shady real-estate agent is now attempting to seize it. Assisted by Juuzou, her grandfather’s student, she starts looking for countermeasures and learns about a strange festival called the "Killing of the Phoenix". Agreeing to take over as chief priest, Sakuya will do her best to revitalize her declining hometown and shrine by resurrecting the "Killing of the Phoenix"!

(Source: Kodansha, translated)