On 20.03. your protagonist finds a thick envelope in his mailbox.

With squiggly, old-fashioned writing, someone has neatly written his address on the envelope in black ink.

The sender is not visible, and the postmark on the stamp contains only yesterday's date.

Inside is a rolled up parchment.

It says:

Dear Ms. / Mr. ...

we congratulate you on winning our competition.

A memorable evening full of surprise dinner awaits you.

As promised, the host and the location of the event are still secret and will only be revealed in the course of the evening.

Please dress appropriately. These are listed below, along with any other details that may be necessary.

You will be picked up on 01.04.2020 at 17.00 o'clock.

This event will be unforgettable for you.

The strange thing is only - your protagonist has never participated in a contest.

Hints:

April fool's joke from boyfriend/girlfriend/other people?

A nice surprise?

Or did someone secretly take part in a competition on behalf of the protagonist?

It could also be someone who has an eye on the protagonist - for whatever reason.

The somewhat old-fashioned address could simply have been deliberately chosen to emphasize the mysterious flair - but maybe it's also a kind of (crime) dinner that takes the guests into another time?

Or one actually travels into the past? Maybe in Dracula's castle? A knight's banquet?

The place and what happens there is completely open. Disco, party, costume or masked ball?

The details could also include the possibility of taking an escort with you, who does not want to send his protagonist into the unknown alone.