As their family gradually begins to change after her return, her older brother Seo-jin grows suspicious and seeks to uncover his sister's secret, which leads him to a shocking truth.

[2][3][4] The movie will be available exclusively on iQIYI with multi-languages subtitles in Singapore, Malaysia, Brunei, Vietnam and Philippines in September.

Kang Seo-jin (Kim Mu-yeol) is an architect who lost his wife nearly six months ago in a hit and run accident.

Stricken with the grief of not finding the driver responsible, he struggles to manage his work and take care of his daughter.

Seo jin gets a call from an orphanage that claims that his long-lost sister was found after 25 years, Kang Yoo-jin (Song Ji-hyo).

[7] Mystery thriller film Intruder (screenwriter Son Won-pyeong, distributed by ACEMaker Movie Works, produced by BA Entertainment) confirmed the lead cast and started shooting on February 13, 2019.

[8][9] Intruder was originally set to be released on March 12, 2020[10] but was postponed because of COVID-19 pandemic outbreak.

The last film to surpass 40,000 moviegoers at the Korean box office on its first day was Beasts Clawing at Straws released 107 days prior on February 19—and widely considered the last film to be released in Korea before the COVID-19 outbreak effectively shut down the movie theater industry.

[15] Intruder topped its first weekend box office with 238,417 admissions and constituted 63.3% of the total ticket sales.

[16] In Malaysia, Intruder placed at Top 2 Box Office Movies in GSC Cinemas on the weekend for two consecutive weeks after its screening on July 23, 2020.