One sunny day, Nikita, who owns a successful veterinary clinic, learns that he is terminally ill. Unaware that this is merely a medical mistake, he serious ponders: who will take care of his beautiful wife, children, and business? The sad thought occurs that it's time to look for his replacement. So after a rigorous selection process, he chooses Ilya, a reliable man with no bad habits, and begins a cover operation code-named "swap." And when Nikita learns that his health is not in danger, it's too late--his chosen replacement loves everyone, including veterinary patients, and everyone loves him. The struggle for life and love is just beginning.