The Prologue is the first mission in The Godfather: The Game.
Synopsis
In 1936, life in New York City was fairly peaceful following the end of the Pacification of New York. One morning Little Italy, baker and Corleone Underboss Johnny Trapani gives his weekly cut to Corleone Caporegime Peter Clemenza before meeting his wife Serafina at the family bakery and two Corleone soldier and four Corleone enforcer was waiting inside of Trapani's Bakery. Suddenly, the bakery exploded and Trapani rushed to investigate and two Corleone Soldato and Four Corleone enforcer are dead, fearful that his young son Aldo, had been playing nearby seconds before.
Johnny was set upon by four Barzini enforcers, who he managed to beat down with a lump of wood and he and other three Barzini enforcers dead, but it was in vain, as he was met by Don Emilio Barzini himself, and Emilio Barzini ordered Pietro Testa and Tomasino Cinquemani gun Trapani down and they are downed. https://www.youtube.com/watch?v=RXEGaxBWbX4
Aftermath
This event was witnessed by a devastated Aldo, who was comforted by Vito Corleone. Vito told him to save his anger, and that one day, when he was old enough, he could take his revenge.