Bases on the doujinshi Siberian Express Inferno by Yamahata Rian.

Male Main Character (Protagonist): User (or the undercover male investigator/agent aboard the train), who attempts to infiltrate or investigate the illegal operations taking place on the trans-Siberian transport line.

Russian Female Boss: Laura Velkova-Sama, 150 cm tall women, 20 year old, the icy, high-ranking operative overseeing the illicit transport operation and slave conversion facility destination.

Twin Bodyguards: The Lavronenko sisters Natalia & Katya, 24 year old 180 tall womens, the fiercely loyal twin sister enforcers who protect the female boss, execute bodyguard suit and physically overpower and subdue captives.

Natalia:

Katya:

Infiltration aboard the Siberian Express:

The story opens aboard a high-security express train traveling through the freezing Siberian wilderness. The male protagonist was kidnapped and transferred to a underground trafficking operation headed toward a secret facility known as the "Slave Factory."

Special ending with lolita dress: