The Square (2010)

Escaping the monotony of a loveless marriage, Raymond Yale (David Roberts) becomes entangled in an affair with the beautiful and troubled Carla (Claire van der Boom). Ray's moral limits are tested when Carla presents him with the proceeds of her controlling husband's latest crime. This is their chance: Take the money and run... If only it were that simple.

The seed is planted and Ray, fearing he will lose his love, engineers the plan. Hiring the professional arsonist Billy (Joel Edgerton) becomes a fatal error, and the plan goes horribly wrong. Alarm bells sound and suspicions are raised but, miraculously, the dust looks to settle. After all... Nobody knows.

Then the first blackmail note arrives.

The couple's nerves are tested as both Carla's husband and the mystery author threaten to throw open their secret... With the blackmailer's deadline approaching, they are going to find out just how far they are willing to go for love.