Question

The black coloured envelope was lying right outside my door surely it must be a mistake . Who would write a letter? But the envelope had my name and address dearly written on it

Answer 1

Explanation:

There are various possibilities u could build up on....

1. You can write a out mythical stuff like Harry Potter...... like u are being accepted in some world which u know not of.
2. You can write about a criminal who is blackmailing u about your family's wellbeing and playing a game with u
3. or ur friends pranked u
4. Or someone is trying to reach to u for help but wants to be anonymous
5. Someone trying to warn u about imminent dangers or plans for u

See the list just goes on....just pick one

and develop on the plot

Hope it helped!