Snegurochka of the Spring Breeze

Set in the Soviet Union in 1920, the mysterious girl named Belka and the quiet boy Shchenok help a Socialist Party member to escape from the secret police. Their aim is to infiltrate into a certain mansion that holds what they seek, but the secret police immediately capture the two. Will they be able to find what they seek and endure the torture of the secret police? (Source: MangaHelpers)