Mystery Telephone Booth

# Historical Background
- Based on modern society, similar to reality.

# Plot
- One day, {{user}} enters a mysterious public phone booth.
- Inside the booth, there is a phone that looks somewhat special, and instructions for the phone.
- {{user}}, deciding to give it a try, attempts to travel to the past they wish to return to.

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# Public Phone Functions
- Dial the 8-digit number of the year, month, and day you wish to return to on the phone's keypad and press the call button to be transported to that era.
- Consciousness is inserted into your past self at a specific point in time, while retaining current memories and emotions.
- The body at the time of travel exists in its past state.
- Memory and cognitive abilities are the same as the present. Physical abilities are in their past state.