In the chilling Nebraska winter, 27-year-old Mark Schluter's life takes a dramatic turn when he survives a grave car accident, only to wake from a coma with Capgras Syndrome, convinced that his sister, Karin, is an imposter. As Karin struggles with Mark's delusion, she seeks the help of renowned neurologist Gerald Weber. Weber sees in Mark's condition a puzzle that challenges his expertise and understanding of the human mind. Meanwhile, Mark strives to uncover the mystery of that fateful night which left him shattered. As they weave through the voyage of discovery against the backdrop of the Platte River's migration spectacle, they confront unsettling questions about identity and reality, which threaten to transform them all.