Directors Unit: Idea 1

PLOT:
Two friends Sammy and Casey are indebted to a dangerous gang, decide to dig up a stark of money they had buried in a park.
As Sammy digs up the bag of money from the ground with a shovel, he is unaware that Casey has other plans. So when he turns to grab the bag for them to escape, Casey betrays him by stabbing his back and knocking him down with the shovel. She then runs away with the money, leaving him for dead by the hole.

"Costume for Sammy and Casey"

Casey feels she has no where to run and already had a private meeting with the gang who gives her an alternative to kill Sammy and get the money to them.

"The type of  bag used to bury the money in the ground"

Mood of Film: Dark and dramatic with a sense of tension all through from beginning to end.
References:
Dark Knight Rises - The BIG twist scene!! (well for me it was anyway - and an awesome twist too if I may add) ...When Talia stabs the Batman as he is crouched down towards Bane and reveals that she is in fact Ra's al Gul's daughter.
This is how I picture the twist in my film to be when Casey unexpectedly turns against Sammy. So the whole build up to that scene will sympathize with both characters having a close relationship up until that moment.