Souta's mom left him and his dad to live by themselves, and suddenly returned when Souta's dad won a rookie novelist award.

When Souta and a girl, Sanae, were hiking one day, they run into a dog searching for its lost owner.

From Wingtip Cafe:

In Edo (ancient Japan), an oiran (high-class courtesan) joined a robber gang that stole from the rich and gave to the poor. Together, they battled against the enemy who used ‘Eleki’ (electric gadgetry and dolls) as weapons.