It introduces the central conflict in the story: Isabella's quest to determine the writer of the love letters.
Explanation:
The complicating incident, also known as inciting incident, is the part of the story that serves as the starting point for the action to happen, it is the main point that captures the audience, and is a significant moment for the characters. In A Modern Love letter, the moment when Isabella finds a letter with a message that says "I've finally found you", and she has no clue of who could have written it, so she is determined to solve the mystery is the inciting incident of the story, it serves as an indicator of what's going to happen, and engages the audience to find out the mystery too.
