On a cold December day, Kyon arrives at school prepared for another outing with his fellow SOS Brigade members. However, much to his surprise, he discovers that almost everything has changed completely: Haruhi Suzumiya and Itsuki Koizumi are nowhere to be found; Mikuru Asahina does not recognize him at all; Yuki Nagato is a regular human; and Ryouko Asakura has mysteriously returned. Although he is no stranger to the supernatural, Kyon is disturbed by this odd turn of events and decides to investigate on his own.

Finding himself to be the only person that is aware of the previous reality, Kyon is now faced with a difficult choice: to finally live the normal life he has always wanted, or uncover a way to turn back the hands of time and restore his chaotic yet familiar world.

Suzumiya Haruhi no Shoushitsu won the Theatrical Film Award at the Animation Kobe Awards in 2010. The film earned an estimated 200 million yen in its first week of release in Japan; it also placed in the top 10 for Japanese box office sales in its first weekend.

The film was released on Blu-ray and DVD in Japan on December 18, 2010. The movie was released on the same formats in North America by Bandai Entertainment as The Disappearance of Haruhi Suzumiya on September 20, 2011. It was later republished by Funimation Entertainment on May 30, 2017.