The first things that happen in a movie are called the start, spark and exposition. The start of Grease is when the "T-Birds" are standing around talking. As they are talking, they see their other member Danny talking to some girls. He comes over and talks to the rest of the group.
I feel this is the start because it is the first thing that happens when the credits begin to show. The spark of Grease is when Sandy starts telling the "Pink Ladies" about the guy she met over the summer at the beach. The guy she met was Danny and she didn't know that he attended the new school she was in. I think this is the spark because this starts the problem of Danny and Sandy getting together. After Danny had his ego sky high he realized that he really shouldn't have done that and he really wants Sandy. In the end, the pink ladies try to get Danny and Sandy back together by changing Sandy into someone that they feel Danny will be attracted to.
The exposition is when the problem is exposed and the characters are introduced. The main problem is getting Danny to act himself and get Sandy to like him again. This is a problem because throughout the movie Danny has to prove himself to Sandy that he wants to be with her after he acted like a jerk. The main characters are Danny and Sandy. The t-birds are Sonny, Kenickie, Doody and Putz y. The pink ladies are Rizzo, Jan, Martie and Frenchie.
These are the characters that the movie plays around from the first day of school until the end at the carnival. These are the three beginning parts that take place in all movies.