The film revolves around a business-oriented high school student, Sohee (Kim Si-eun), who has to go on field training to her call center, and a female detective, Yu-jin, who investigates her subsequent death.

[5] The film is about Sohee (Kim Si-eun), a high school student who starts training for a subcontracted position at a call center.

Before starting her externship, Sohee has to attend a training session which turned out to be just makeup lessons as well as body shaming of the trainees.

While on leave and suffering from the guilt of signing the form stating Junho's claims of the company mistreating externs were false, Sohee silts her wrists while on a drunk night out with a friend and is subsequently hospitalized.

Depressed at the prospect of returning to the call center and slightly intoxicated from drinking alcohol, Sohee commits suicide by jumping into a reservoir after a night out with friends.

The second half of the film follows the investigations of Yoojin, a female detective officer into the suicide of Sohee after her body is found as well as reinvestigations of Junho's suicide, which further details Human and Net's violation of labour laws on their workers in order to drive up sales as well as Sohee's high school's irresponsible choices of externship placements for their students in order to meet an employment rate.

Throughout the investigations, human and net and the school's management constantly blame Sohee for her own suicide citing that she was undisciplined and had temper issues.

However, Ide criticized her writing, stating, "this has the feel of a screenplay which could have benefited by a sharper focus and a leaner approach to its storytelling.

In the second half Bae Doona takes over the story as detective Yoo-jin, where she investigates Sohee's demise and seeks justice.

Concluding his review, Tsui wrote, "Jung has stirred up a stink with a film that's visceral to the extreme in revealing the dark dealings that make an economy click, and a steep warning about the possibilities of more Sohees to suffer from such indignity and injustice.

"[33] Elena Lazic writing for The Playlist criticized the director's approach on handling the film, writing, "the director opts for a less believable and more dramatic blunt-force approach, rather than portray her [Sohee's] experience there as one that slowly comes to affect her mind and priorities until her warped sense of priorities and self-worth leads her to end her life."

[34] French critics site Le Bleu du Miroir praised the performances of actors and screenplay writing, "Magnificently carried by its two actresses, neat in its writing and in its staging without fuss but always at the service of the story and its characters, Next Sohee asserts itself as an excellent closing choice for Critics' Week and confirms the promises of a filmmaker to follow.

Concluding Kotzathanasis wrote, "Next Sohee is an excellent drama that highlights the issues with the Korean system and their consequences in the most pointed but also rewarding way.