Answer:
This question requires a personal answer about something that happened to you. Anyway, I will give you an example story so you can understand how to write it, and in case you want it, you can change it for something personal.
Step-by-step explanation:
There was a time when I decided to surprise my best friend for her birthday.
She moved to another country two years ago and I had never been able to visit her, but we talked daily anyway.
My parents bought me the plane ticket, and together with her sister we planned the surprise. The idea was that when she got home from school, I would be waiting for her at her house with a birthday cake.
I would arrive that same day to prevent my friend from seeing me before the right time. But a problem happened. That day my friend felt sick so she did not go to school!
Her sister couldn't go to the airport for me because otherwise the surprise would be ruined.
I was waiting there without knowing what to do for an hour, until my friend's mother decided to take her from the house with the excuse that they had to look for something at grandmother's house. At that moment, my friend's sister took advantage and went to find me.
By the time my friend came home I was waiting for her there with the cake! Everything went very well and she was very excited to see me there.