Janu, a kind-hearted high school student known for his helpfulness, is fighting for his mother’s life, doing whatever it takes to afford her treatment. After school, he bravely chases down a thief, but his true battle lies at home—his mother, Sari, suffers from kidney failure. One day, as Janu and his friend Aji finish their classroom duties, they notice an AS card slipping from their teacher's pile of documents, revealing a place where all the bad kids are united, and who knows what that place is really about.

Janu picks up the Ace of Spades card that had fallen from the stack of documents. Aji approaches a confused Janu, and together they flip the card, revealing a message: "Open Fight" with an address underneath: "Benteng Utara." Curious, Aji urges Janu to visit the place. Though hesitant at first, Janu eventually agrees, pushed by Aji and his own curiosity. When they arrive, they discover the location to be an illegal fight arena for high school students. Pressured by circumstances, Janu is drawn into the fight, ultimately defeating the strongest fighter there.

In the crowd, Jack is intrigued by Janu’s victory and throws a Jack of Spades card, challenging him to a "Double or Nothing" fight. Pressured by the crowd, Janu accepts and defeats Jack. As they leave, a robber steals their bag of money, leading to a chase. After a fight on a bemo, the robber escapes, but drops a wallet with a Queen of Spades card, revealing the address to Queen’s headquarters. Exhausted, Janu and Aji head home.