After you defeat Meganyan, Hovernyan uses a Time Stone to send you back 60 years to help your grandfather.
This Is 60 Years Ago?
Go into Grandma's house. After that, go outside and there will be a cutscene. Then go north of the creek and go west, and cross the plank of wood to the south side of the creek. Go west into the forest. Go north to enter the secret base.
After the cutscene, check on the table on the left side of the secret base to see Nathaniel/Kenny's plans for making the Yo-Kai Watch.
Wicked Yo-kai
Now you need to go to Timers & More, the Mount Wildwood Shrine, and the Springdale Ironworks to get the parts that Nathaniel/Kenny needs to make the Yo-Kai Watch able to see Wicked Yo-kai.
Creating the Yo-Kai Watch
Go southeast to reach Harrisville Station. After the cutscene, go to the left of the station and use the Yo-Kai Lens to find a Yo-kai. Talk to it to befriend Miradox.
After that, go to the right and walk into the station. Pay $3 to buy a ticket.
The Ironworks's Part
In Old Springdale, go to the left, then down, then right, and approach the entrance of Springdale Ironworks. After the cutscene, go east and talk to Nick Nack. He gives you a Mysterious Marble.
The door to the Ironworks is above you. Check on the door to go in.
After the smog Yo-kai disappears, go around the building looking for objects that are moving by themselves. Check on them. Eventually, there will be a statue on top of the raised platform in the upper-middle part of the building. Check on it and you will have to battle. After you win, the quest is complete.
The Shrine's Part
Go north to the Mount Wildwood Shrine. Go up to the shrine building and then use your Yo-Kai Watch near the bottom-right corner of the shrine to find a Yo-kai. Talk to Komajiro.
Then go south to Galleria Boulevard, which is where Flower Road is in Shopper's Row in the present time. Go to the lower part of Galleria Blvd and go through the east exit. Then go east and check on the fox shrine.
Then go back to the Mount Wildwood Shrine and talk to Komajiro. He will give you the Swirly Bell.
Timers & More's Part
Go northwest to find Timers & More. Go inside and talk to Mr. Goodsight. Then go to the train station and take the train back to Harrisville. Use Miradox to go back to your own time.
From modern-day Harrisville, take the train to Fortune Point, then transfer to the Central line. Try to wait for an Express train if you want a shorter ride. Get off the train at Springdale Central Station. In the station, talk to the Mirapo in the upper-right.
In Downtown Springdale, go to the restaurants west of the station and go into Belly Buster Curry. Talk to the girl behind the counter. She gives you the Heckapeño.
Go back to Springdale Station and talk to Mirapo to warp back to Grandma's House. Then you can go down to the bus stop and take the bus to Harrisville station. When you arrive, go to the Eyepo and talk to the nearby Mirapo. Then go to the left and talk to Miradox to go back to the past.
Then go into the Harrisville Station and take the train to Springdale. Go back to Timers & More and talk to Mr. Goodsight.
Moximous and Bold Basher
After getting the Top-Notch Watch, take the train back to Harrisville Station, then talk to Mirapo to go to Harrisville. Go into Nathaniel/Kenny's secret base to finish this chapter.