Watch TV Series On Call Prime Video Online Free. On Call is an adrenalized procedural that puts us inside the squad car and on the streets with Long Beach Police. Through training officer Traci Harmon, and rookie Alex Diaz the series examines how the complexities of the job affects the human condition. Harmon will be enlightened by a kid from the streets, while Diaz will learn that policing isn’t black and white – it requires shades of grey.