Someone is tampering with the water supply in the small Brazilian community, causing many to get sick, including Pilár Silva's beloved grandmother. Pilár leaves Chicago and travels to Salvador, Bahia at the start of Carnival season. She must trust Yoshi Tanaka's expertise as a scientist and his abilities to keep her safe.

Yoshi, an award-winning Hydrologist, is supposed to stay in Rio for a conference, but he honors his brother's request to help a co-worker from The Castle who's in the region. To keep Pilár safe, he must keep her close.

Danger stalks them like a thief in the night. Will they explore their budding feelings, or will one of them end up in a shallow grave?