Suzume No Oyado No Katsudou Nisshi Wiki

Miyama Onsen Grand Shrine and Restaurant: Enma-tei
Sparrow's Inn Daily Report ~Records of the Enma-tei's Prosperity~

While Master was enjoying the bustling festivities of the New Year, an emergency call comes from the Command Room. The briefing this time details an all but harmless Singularity that appeared quite suddenly at a mountain hot springs resort. As such, the suggestion was to Rayshift there for a bit of rest and relaxation. Accompanied by the Servants who were drawn out by rumors of a hot springs trip, Master eagerly Rayshifts!
...But for some reason, everyone finds themselves in a deep forest overrun by a band of mischievous monkeys. After they save a mysterious sparrow from the primates' attack, it invites them to a nearby hot springs inn as a demonstration of gratitude for their help.
The inn looks magnificent at first sight, but behind its grandiose exterior, something seems off...

A limited time New Year event in Fate/Grand Order, released on the Japanese server on January 1, 2019 and on the NA server on January 1, 2021.