Ramen With Unknown Flavor / Running Ramen / Accepting Challenges!!

Yū becomes curious about a mysterious blue ramen that Koizumi was eating. Shū invites Yū to a conveyor belt sushi restaurant where they spot Koizumi enjoying one of its ramen dishes, prompting them to order some themselves. Later, Jun invites everyone to a Chūka restaurant in Kagurazaka to help her eat a massive gyōza her mother had reserved, with Koizumi ordering countless ramen dishes on top of it.