Melvin Udall, a cranky, bigoted, obsessive-compulsive writer of romantic fiction, is rude to everyone he meets, including his gay neighbor, Simon. After Simon is brutally attacked and hospitalized, Melvin finds his life turned upside down when he has to look after Simon's dog. In addition, Carol, the only waitress at the local diner who will tolerate him, leaves work to care for her chronically ill son, making it impossible for Melvin to eat breakfast.

Perpetually single Frankie decides to give up on men in favor of going all-in as a “dog mom" to her adopted dog, Tucker. But sparks fly when Frankie meets Jack, the veterinarian who rescues her dog from near death. They seem destined to be together, but there's one problem: Jack is already engaged.

This heart-warming documentary shows true stories about the unconditional loyalty between humans and dogs and investigates our best friends' remarkable intelligence, their outstanding sensory abilities and emotional bond to us humans.

He has shared our lives for 20,000 years. Along the way, he has helped us find food, kept our livestock, protected us from our enemies, guided us in extreme conditions, and saved us from peril. Now, he comforts us, relieving loneliness and helping us cope with old age. How did dogs come about?