I'm sure I'm dead, but how am I alive...?

Guests gathered for a banquet to celebrate Albert's birthday, which will be held four days later.
However, for some reason, the protagonist fails to meet the banquet day four days later and returns to the first day after he dies.
Who was the culprit who drove the main character to death?
And why repeat the endless return of death?
In the middle of winter with a blizzard, a whirlwind of emotions swirls among the guests trapped in the mansion...
What is the truth about a closed circle mystery murder case set in the Victorian era?