Lanterns Episode 6 was essentially a clean slate for the HBO series, as it opens with John Stewart as an architect in Midway City, in the present. This week's episode was all about setting up the board for John Stewart's investigation into Hal Jordan's murder. The closing minutes of the sixth episode set up this plotline, as John Stewart summons Hal Jordan's backup consciousness, which is stored in the ring.Thus, the preview for next week's episode reveals the return of the younger, 2006 Hal Jordan or "Halogram". Halogram will help John solve the mystery at the heart of the DCU HBO series: Who killed Hal Jordan? And, if fan theories are to be believed, Hal may indeed be dead in Lanterns.Lanterns Episode 7 preview shows John investigating Hal's death:The 43-second teaser focuses on John and "Halogram" trying to solve who killed Hal Jordan. It seems that Halogram is paranoid about solving his human counterpart's murder, and backup consciousness is on the edge throughout the preview. It also reveals that John will be facing some issues of his own in the upcoming Lanterns episode.The sixth episode reveals that John Stewart's relationship with both of his parents is strained. Thus, the preview shows us that John will have to confront these issues head-on if he ever wants to become the third human Green Lantern. But one moment stands out in this preview: John punching a mysterious figure. While we don't know who the figure is, some fans have theories.Fans believe that John finally meets Sinestro: View this post on Instagram Instagram PostThe midseason trailer already revealed that John interrogates Sinestro in a mysterious location. This week's Lanterns episode already revealed that Sinestro was broken out of prison, and Hal would have been a suspect, had it not been his decade-long incarceration. Thus, John might consider Hal's mentor turned enemy as the first suspect in Jordan's murder mystery.Sinestro was advising Hal to kill John. Thus, next week's episode could see the former Green Lantern Corps candidate turned architect confront Sinestro. Moreover, the next episode could also confirm a prevalent fan theory: Lianna might be Sinestro's ally, and she might be the one who told him about John in the first place.Fans believe that Lianna might not even be a guardian, but rather a Manhunter herself. Therefore, next week's penultimate episode might be a key entry as we might be given some key revelations such as the identity of Hal Jordan's killer, and if he is really dead."The series follows new recruit John Stewart (Aaron Pierre) and Lantern legend Hal Jordan (Kyle Chandler), two intergalactic cops drawn into a dark, earth-based mystery with cosmic ties as they investigate a murder in the American heartland."The penultimate episode of Lanterns airs on HBO next Sunday on September 27, 2026.