Last Resort
The Legendary Lake Yokai: The Bond of Usagi's Family
Mizuumi no densetsu yokai! Usagi kazoku no kizuna
"Usagi goes on a family vacation to the hot springs, where she is unexpectedly reunited with Mamoru. But due to the Dark Kingdom's brainwashing, Mamoru no longer remembers Usagi or even who he really is." (source)