Star Trek: Discovery season 2 episode, "Perpetual Infinity", centered on the time-travel conflict between Michael Burnham and her mother Gabrielle, and it was a poignant echo of "The Visitor", one of the best episodes of Star Trek: Deep Space Nine. That classic episode was about Jake Sisko, another child who lost his parent, Captain Benjamin Sisko, to time travel.

The various Star Trek series tend to focus on the friendships and 'found family' among the crew of a starship (or space station) and usually when a blood relative is introduced, they pose a problem to be solved. For instance, Sarek and Spock were hardly on speaking terms during The Original Series, Captain Picard was estranged for many years from his brother Robert on Star Trek: The Next Generation, and Worf not only didn't get along with his brother Kurn, but his son Alexander resented him. The loving father-son relationship between Benjamin and Jake Sisko, which was the heart of DS9 for all seven seasons, is the exception. The Siskos defied Star Trek's typical conventions and told a long-form story of a son who grew up with a soldier for a father, didn't want to follow in his career footsteps, but nonetheless, loved and admired his dad. Ben, in turn, always made time for Jake and strived to be the best parent and role model possible.

Related: Star Trek: Discovery Homages Wrath of Khan (And What It Reveals About Spock)

Thankfully, Star Trek: Discovery followed the mold of the Siskos when the prequel series finally introduced Michael's mother, Dr. Gabrielle Burnham (Sonja Sohn), who Michael thought was dead for the last 20 years, but was revealed to be the time-traveling being known as the Red Angel. When mother and daughter came face-to-face in "Perpetual Infinity", Star Trek: Discovery touched on notes that were powerfully reminiscent of the classic DS9 season 4 episode, "The Visitor".

"The Visitor" was told as a flashback where Jake Sisko (Tony Todd), who was a dying old man, told a young writer the story of how he lost his father Ben to an accident when he was 18. At first, Captain Sisko was believed to be dead but he began reappearing to Jake as the son aged. Jake learned that his father was actually trapped in subspace, where he wasn't aging or experiencing time, but they were tethered together. Jake gave up his marriage and his career as a writer and spent the rest of his life learning the science necessary to bring his father back. Finally, in his old age, Jake realized that he was the cause of the tether, and he committed suicide to restore his father back to the point of the original accident, setting the timeline back on course.

In "Perpetual Infinity", Gabrielle Burnham used the Red Angel suit intending to save her family from a fatal Klingon attack, but instead, she was pulled 950 years into the future where the Control A.I. had wiped out all sentient life in the galaxy. Gabrielle spent the next 20 years time-traveling but always being pulled back to the apocalyptic future by time's tether. She continually failed to alter the timeline and save the galaxy, but during her 841 attempts, Gabrielle also watched out for her daughter Michael without her knowledge, even once coercing a young Spock to save her life on Vulcan. After their brief, bittersweet reunion, Michael lost her mother again at the end of the episode when Gabrielle was pulled back to the future but without the Red Angel suit, meaning Michael may have lost her forever.

Both episodes deal with heady, time-travel paradoxes but more importantly, they are about the power of filial bonds and sacrificing yourself to save your family. "Perpetual Infinity" flips the script and makes it about a mother giving up hope that she'll ever be part of her daughter's life again, but that saving the galaxy and Michael is worth that price, with Sonequa Martin-Green and Sonja Sohn delivering emotional performances equal to Avery Brooks, Cirroc Lofton, and Tony Todd.

"The Visitor" remains a Star Trek classic nearly 25 years after it aired because of how it hammered home Jake's love for his father, despite Ben urging him to let go and live his life whenever the elder Sisko reappeared to his ever-aging son. Thankfully, Star Trek: Discovery gave Gabrielle and Michael Burnham a story worthy to be regarded alongside Ben and Jake Sisko's.

Next: Star Trek: Discovery's Red Angel Reveal Was A Good Twist (But Poorly Executed)

Star Trek: Discovery streams Thursdays @ 8:30pm on CBS All-Access and internationally the next day on Netflix.