Detailed Explanation
Rachel's murder drives the entire plot of His and Hers. The show deliberately misleads viewers through its dual narrative structure - we see events from both "his" and "hers" perspectives, but neither narrator is trustworthy. The killer's identity is connected to the dark secrets both Jack and Anna have been hiding, and the finale recontextualizes earlier scenes in devastating ways. The revelation involves betrayal, obsession, and the lies couples tell each other.