"Baccano!" is a manga series adapted from the light novels written by Ryohgo Narita, with illustrations by Katsumi Enami. The story is set primarily in the United States during the early 1930s, weaving together multiple interconnected narratives that span several decades. The central plot revolves around immortality, alchemy, and the chaotic lives of various characters whose fates intertwine in unexpected ways.

The narrative begins with the creation of an immortality elixir by alchemists in the early 18th century. This elixir grants eternal life but comes with a curse: those who consume it cannot die unless devoured by another immortal. Centuries later, in 1930, the elixir resurfaces aboard the transcontinental train, the Flying Pussyfoot. The train becomes a battleground for rival gangs, including the Russo mafia, the Lemure cult, and the Martillo Family, all vying for control of the elixir. Amidst the chaos, a group of immortals, including Isaac Dian and Miria Harvent, a pair of eccentric thieves, and the enigmatic Szilard Quates, become entangled in the conflict.

The story also delves into the origins of the immortals, revealing their connections to the alchemists and the tragic consequences of their eternal lives. Key characters include Firo Prochainezo, a young member of the Martillo Family who becomes immortal after drinking the elixir; Ennis, a homunculus created by Szilard; and Ladd Russo, a violent and unpredictable gang leader. The narrative frequently shifts perspectives and timelines, creating a complex web of events that gradually converge to reveal the full scope of the story.

Themes of fate, morality, and the human condition are explored through the characters' interactions and the consequences of their actions. The series blends elements of action, mystery, and dark humor, with a focus on the unpredictable nature of life and the interconnectedness of seemingly unrelated events. The manga adaptation captures the intricate storytelling and vibrant character dynamics of the original light novels, offering a visually engaging and narratively rich experience.