Episode 4 of "Paradise" unfolds with an illuminating glimpse into Billy Pace's tumultuous past. He was reared in the untamed Wild West, under the oppressive thumb of his Uncle, a man whose dominant and overpowering presence loomed large in Billy's life. When the uncle threatened to harm his loyal canine companion, Billy's instincts kicked in, and in a fit of protective fury, he shot the man. This tragic deed sealed his fate, leading him down a dark and troubled path, where he spent the better part of his life incarcerated, his aggression and dangerous demeanor escalating with each passing day. Eventually, he was liberated by a mercenary who saw potential in his ruthless disposition, enlisting him as a cold-blooded "killing machine."
Cutting to the present, Collins bids farewell to Gabriela and makes a brief pitstop at his own abode before setting off to Billy's place. As he delves into Billy's files, uncovering the gritty details of his prison stints and past misdeeds, he is transported back to their first encounter, when both were on the brink of embarking on their journey to Paradise. Despite Billy's violent past, he had once opened up to Collins, confiding in him about the struggles he faced in the old world and how, in this new realm, he finally felt a semblance of "normality." Their bond grew stronger, to the point where Collins' children affectionately addressed Billy as "Uncle."
While Collins is engrossed in examining the files, Robinson catches him in the act. Meanwhile, at the carnival, Collins persists in his quest to find Billy. A flashback reveals Collins grappling with the uncertainties of life beyond Paradise, even as the president reassured everyone that no signs of life existed outside. To provide solace to those mourning the loss of a potential future beyond their confines, the president dispatched four scientists on a mission to assess the external world's condition.
Collins eventually confronts Billy, but his suspicions about Billy being the president's killer are swiftly dispelled. Billy passionately asserts his love for Collins' children, insisting that he would never harm them. However, another bombshell revelation drops—Billy was indeed part of a clandestine mission to eliminate the surveyors sent beyond Paradise's borders. The orders had originated from Sinatra himself, who was determined to prevent anyone from escaping their artificial utopia.
Later, Billy confronts Sinatra head-on, issuing a stern warning for her to keep her distance from Collins and his children, whom he has embraced as his own. Yet, Sinatra strikes back, daring him with the threat of exposing his shadowy past or deploying another hired killer to end his life.
Elsewhere, Billy makes a solemn resolution to unburden himself to Collins the following day, spilling all the secrets he holds. That very night, he returns to his abode to revel in festivities with Jane, his beloved. But as the merriment is about to commence, Billy suddenly succumbs to a mysterious collapse. The truth unfolds: Jane, who has been Sinatra's loyal agent all along, is revealed as the second assassin. She meticulously stages his demise, ensuring that Sinatra's iron grip over Paradise remains unbroken.
