Mantis: Release date news, cast details, streaming details and more about the upcoming K-thriller on Netflix

Lee Tae-sung will soon make his directorial debut with the upcoming K-action thriller titled 'Mantis,' all set for a September premiere on Netflix. The highly anticipated Korean entry shares the same universe as that of the 2023 thriller, Kill Booksoon, by Byun Sung-hyun, and will also feature some popular faces in the tumultuous journey through the secret world of assassins.

South Korean sensation Im Si-wan will take the lead in Mantis alongside his Squid Game co-star, Park Gyu-young. The plot centers around a contract killer who has been on a break from the underworld for a while, but his return to the hitman business turns things awry as rivalry crops up.

Here's a look at the film's synopsis, as per IMDb:

"Mantis, an ace assassin, returns to the contract killer industry after a hiatus, encountering his trainee friend Jae-yi and a retired legendary killer Dok-go, who now runs the organization."

When will Mantis be released? Streaming details, explored

On September 26, 2025, Mantis will have an exclusive premiere on Netflix, and viewers across the globe will be able to experience this thrilling new journey with Standard (with or without ads) or Premium subscriptions (worth $7.99/month, $17.99/month, $24.99/month, respectively).

Earlier in August, Netflix dropped the first teaser of Mantis, followed by the first trailer (last week), and ever since, there has been quite a social media buzz, especially among the K-thriller fans.

What do we know about the story of Mantis?

Money, arms, and deaths: Mantis stands at the centroid of these three vertices of the hitman world. The plot revolves around an assassin named Han-ul (portrayed by Yim Si-wan) who is more infamous by his other identity: Mantis. The titular antihero is well-known for his expertise in the field of contract killing, but for certain reasons, he has been on a vacation for quite some time now.

The backdrop of Mantis' return takes us to the time when the death of the leader of MK Entertainment, Cha Min-kyu, left the whole world in a state of tumult. Following Min-kyu's demise, a retired yet legendary assassin, Dok-go (portrayed by Jo Woo-jin), takes matters into his own hands, trying to re-establish order in the organization.

On the other hand, as Mantis joins the infamous organization, he crosses paths with an old flame and co-trainee, Jae-yi (played by Park Gyu-young), which further adds a layer of drama to the plot. But Mantis soon realizes that things are quite different now, and there is a lot of competition to reach the top of the world of assassins, especially with Dok-go now calling the shots.

The new film, though a spin-off of Kill Boksoon, will follow an entirely different narrative with more focus on the struggle to establish self-authority in the underworld, unlike the 2023 movie (which rather highlighted the struggles of an assassin's life while trying to balance it with family).

Who is in the cast of Mantis?

Im Si-wan will play the titular role of Mantis, aka Han-ul, a contract killer who returns to the world of chaos after a long break. Joining him we have Sweet Home star Park Gyu-young, who will portray Mantis' co-trainee and old friend, a woman named Jae-yi.

The part of Dok-go will be played by award-winning Korean star, Jo Woo-jin, known for his work in War of the Arrows, Venus Talk, The Sheriff in Town, and Kingmaker. SBS Drama Award winner, Choi Hyun-wook, will also be a part of the cast, portraying a man named Benjamin.