As he's living out his amazing slime life, Rimuru decides to record his experiences in a diary... but there are so many, he doesn't know where to start. That's just how life in Tempest goes.

As the seasons turn, Rimuru plans a Bon Festival celebration. Each race has its own history, and the festival is a time to show gratitude and reaffirm their bonds among their own families and clans, and to strengthen friendships by telling others all about their own histories. And with this Bon Festival, Shizu-san returns to Tempest as a spirit...

Most buildings in the monster city of Jura are made of wood, so in winter, a combination of dryness and heating mechanisms can lead to fires. So Rimuru starts up a good old-fashioned fire awareness campaign. Benimaru is selected as the mascot, but he seems troubled by the assignment... And in the midst of all these, the human Youm and his friends arrive in Tempest.

Rimuru said he wanted to do a first shrine visit of the new year, so the citizens of Tempest built a shrine. But what deity is housed at this brand new shrine? Rimuru thought it must be Veldora, the guardian of the Forest of Jura, but everyone else says it's a shrine to Great Rimuru, so he ends up enshrined there... Thus their fun New Year's comes to an end, and Rimuru closes his diary. What will this new year bring? Tomorrow is sure to be packed with enough events to fill a new page...