SS001

is the first episode of the Shadowside animation series, and the 215th episode of the overal Yo-kai Watch animation series. It aired in Japan on April 13, 2018 and is part of the one-hour special alongside with The Bicycle Ridden by the Dead that aired in Japan on the same day.

Summary
It has been 30 years since the lost of the Yo-kai Watch from Nathan's era. ''The arrival of the Demon King marked the end of peaceful, ordinary days. However, Natsume, who was chosen by the new Yo-kai Watch Elder, the owner of the Yo-kai Watch Ogre, Touma, and the practitioner of sorcery, Akinori, along with the Yo-kai that defeated the Demon Lord, brought back those peaceful days of ordinary life once again. And after that, these children went on to establish a Yo-kai detective agency in order to solve mysterious incidents caused by the Yo-kai. Now the curtain rises on a new story.''

''Keisuke Amano a boy that does not believe in the occult follows his older sister Natsume Amano and discovers the secret Yo-kai Detective Agency that was formed alongside her friends Touma Tsukinami, and Akinori Arihoshi. The Yo-kai Detective Team reads a thread on their forum that there is a Yo-kai under the name as the "Phantom Gangleader", that attack bullies and even people who are eye witnesses to those assaults caused by the Yo-kai. Keisuke will learn about the existance of Yo-kai, but is still not fully convinced about it and believes that his sister is in a cult and that she is brainwashed by her friends. The group are searching for the Phantom Gangleader, not knowing that the Yo-kai is in fact someone Keisuke knew.''

Plot
The story being with a boy that walks through the streets and enters an ally until he encounters a large creature that attacks him. On the ground, he screams in terror. Keisuke Amano, a boy who does not believe in the occult follows his older sister Natsume Amano noticing that something is odd. He notices that she comes home late and wonders if she has a boyfriend that might not be bad in his own opinion. But he believe that his sister might be in a cult that forces her to pay them money.

Natsume enters the detective agency and apologizes for being late. Akinori tells her that she is late, but Natsume tells him that she is only late for 3 minutes. Akinori responds by saying that she must stop fooling around as that time is precious. Natsume tells Akinori that he's playing make-believe running an agency. Shocked by it, he explains to her that their important activities influence the faith of the entire world, and tells her that there are many bizarre incidents in modern society that they solve and that they're here to take back the peace, to the relief of the hearts of the people. Natsume then understands that out that they are a collective agency, which stirred up Akinori even more by saying that they are not a collective agency but a detective agency. Outside the agency, Keisuke is wondering which one's Natsume's boyfriend and looks to both Akinori and Touma. Akinori tells both Natsume and Touma that there is something that he wanted to show them. He then shows a forum post about the Phantom Gangleader and explains the situations surrounding about it to them.

Important events

 * Keisuke befriends the Yo-kai Borei Bancho after noticing to be his old friend that has passed away and receives his Ark.

Trivia

 * This episode alongside with The Bicycle Ridden by the Dead, was part of a special giveaway specially for the Japanese audiences.