Ep 17. Trinity

Supergirl season 3 episode 17, entitled Trinity, begins with a tense scene as the leader of Krypton's religious group, Reign, pays a visit to Lena Luthor. Lena is working on a cure for Reign's powers, which are rapidly escalating, but their meeting quickly turns hostile as Reign demands to know what Lena is doing with the Harun-El, the very element that gave Reign her powers in the first place.

Meanwhile, at the DEO, Supergirl is trying to track down Reign while dealing with her own personal crisis. Her relationship with Mon-El has always been complicated, but things come to a head in this episode as she must confront her feelings and decide what she truly wants.

But the main focus of the episode is on the Trinity – Reign, Samantha, and Ruby – and their intertwined destinies. As Samantha struggles with the knowledge that she is the true identity of Reign, Ruby becomes increasingly concerned for her mother's well-being. The trio is forced to confront their individual paths and decide once and for all who each of them truly is.

Meanwhile, the reappearance of Winn's estranged mother provides some levity to the episode, as she gets caught up in the DEO's latest mission and proves to be surprisingly capable. Winn also gets to show off his engineering skills as he creates a new weapon to combat Reign.

Overall, Supergirl season 3 episode 17 is a riveting installment that expertly juggles multiple storylines and character arcs. The focus on the Trinity adds an extra layer of drama and tension, and the episode is further elevated by standout performances from the talented cast. Fans of the show will not want to miss this exciting chapter in Supergirl's ongoing battle against evil.