Ian McEwan Website
http://www.ianmcewan.com/bib/books/atonement.html
A Web site dedicated to the entire works of Ian McEwan.
The Question and Answer section for Atonement is a great resource to ask questions, find answers, and discuss the novel.
Throughout the novel, there are repeated refernces to the "three figures in the garden" from Briony's story. These three mysterious figures foreshadow events that will occur and lend an air of mystery to the story that Briony is telling.
They meet once for half an hour, during Cecilia's lunch break. Their reunion starts awkwardly, but they share a kiss before leaving each other.
Check out misunderstanding/perception below:
https://www.gradesaver.com/atonement/study-guide/themes