Following last week’s “The Red Angel,” which focused on advancing many of the character threads of this season, “Perpetual Infinity” is a solid Michael Burnham episode that pushes ahead with the main plotline from this season of Star Trek: Discovery.

Many of the mysteries of this season now lie revealed. The enemy this season is an advanced artificial intelligence – Control – who began life as Section 31’s threat assessment program who evolved itself thanks to access to advanced knowledge from the sphere encountered by the Discovery in “An Obol for Charon.”

The Red Angel, on the other hand, is Gabrielle Burnham (Sonja Sohn), the biological mother of Michael Burnham (Sonequa Martin-Green).

Michael had thought her parents killed in a Klingon raid on Doctari Alpha when she was ten years old. However, in reality, Gabrielle had attempted to activate the untested time travel suit that she and her husband Mike Burnham (Kenric Green) had invented for Section 31 to go back in time and avoid the Klingon raid.

Green, husband of series lead Sonequa Martin-Green, makes his first appearance on the series playing the Discovery science officer’s namesake; his participation in Season 2 was first teased by Martin-Green all the way back at New York Comic Con in October.

Instead of materializing an hour in the past, Gabrielle ended up 950 years in the future, at a point in the timeline when Control had wiped out most life in the galaxy. Faced with the desolate cosmos, Gabrielle dedicates herself to using the suit to travel back and try to stop Control from securing the information it needs to evolve itself.

As a result of her travel into the future, Gabrielle is also tethered to her new time, and can only travel into the past for short periods. It seems as though Gabrielle has spent years trying to stop Control, but each attempt — and change in the timeline — has resulted in failure.

Though this episode did not provide us with detailed explanations for all of the Red Angel’s appearances this season, we did find out the reason for perhaps its most mysterious intervention – why did the Red Angel relocate a group of survivors from World War III to the planet Terralysium 50,000 light-years from home back in “New Eden”? According to Gabrielle’s mission logs that Michael reviewed, it was a test: to see whether history could be permanently changed.

Control and Gabrielle have been locked in a battle across time, and it has clearly worn significantly on Gabrielle’s psyche. In a scene reminiscent of a conversation between Chakotay and Annorax, the Krenim scientist working to change the timeline to restore the might of the Krenim Imperium in Voyager’s “Year of Hell,” Gabrielle does not have a favorable view of time.

Confronted by her long lost daughter, Gabrielle can only respond that “People think time is fragile. Precious. Beautiful. Sand in an hourglass and all that. But it’s not. Time is savage. It always wins. So this is meaningless.”

For Michael, this is not the reunion she expected or hoped for. She finds her mother more obsessed with the mission to destroy Control than to finally have realized her original goal – to return to her daughter. Gabrielle implies that she’s been through various iterations of these events in her previous attempts to change history, though this seems to be the first in which she comes face-to-face with Michael. “I could say more about your future. But you won’t like it,” she ominously tells Captain Pike (Anson Mount), in an apparent reference to Pike’s fate as seen in “The Menagerie.”

“I let you go a long time ago. I had to. I’ve seen you die a hundred times. And I’ll see you die a hundred more,” Gabrielle tells Michael, though by the end of the episode her rejection of Michael is revealed to be a bit of an act. Gabrielle reveals that, using her time travel suit, she has kept close tabs on Michael throughout the years and been present for many of the important moments of her life.

Once again, Sonequa Martin-Green floored me with her performance. The emotional journey she takes in this episode – from disbelief, to hope, to disappointment, to love, to sadness, to hope – is a wrenching journey and Sonequa makes us feel every mile of it. Meanwhile, Sonja Sohn is a delight – determined, fierce, difficult, but ultimately underneath the damage done to her psyche by her trips through time, a loving mother.

The plan to send the sphere data far into the future outside the reach of Control ultimately fails, and Gabrielle’s time suit is rendered useless. She is still pulled back into the future – but hopefully the future she returns to is on in which the events of the remainder of season two of Discovery played out such that Control is destroyed.

I will be curious to see if we revisit Gabrielle, either this season or in the future of the show. She is definitely a great character, though once the Control storyline plays through is there anything additional to explore with her?

While much of “Perpetual Infinity” was fast paced, the episode still found some time to slow down and take a beat. There is a really nice, very Star Trek scene, in which the crew discuss the ethics behind deleting the archive of data that they downloaded from the sphere in “An Obol for Charon.” While it appears necessary for the mission, Saru (Doug Jones) argues for a different path, likening the deletion of the sphere data to the burning of the library of Alexandria.

Despite the galaxy-spanning threat, Starfleet officers taking a moment to pause and debate the merits of their path forward from a purely enlightened perspective is always joyful. Star Trek is at its absolute best in these scenes. Ultimately, the sphere data prevents its own destruction, which is why the plan is hatched to send the data far into the future.

However, that plan is foiled by Control in its latest iteration – recognizing the limits of its holographic disguises from previous episodes, the AI finds a way of taking over the biological body of Leland (Alan Van Sprang) himself.

There were a couple of moments in this episode when I wondered if we were watching maybe watching some kind of origin of the Borg from the Control-Leland (Contreland?) character.

The blood vessels turning black just like during assimilation, and the scene where Ash Tyler (Shazad Latif) finds Control-Leland and his face is being partially rearranged by the technology. The Borg were very old, but this season does have a time travel element to it so a 23^rd century origin (by way of then traveling far into the past) is not precluded.

I am not pulling for it to be the Borg — and I don’t want it to be the Borg — but there are some clear similarities here. (“Struggle is useless” sure sounds like “resistance is futile.”)

If there’s one thing we’re missing so far this season, it’s a really good motivation from Control. One of the reasons I am so in love with David Mack’s novel Section 31: Control is that the artificial intelligence in that novel has a really clear motivation that guides its actions – to protect the Federation at all costs. Discovery’s Control, on the other hand, has not really laid out its logic. Why does it want to control Starfleet? Why will it eventually want to destroy all sentient life in the galaxy?

I understand the threat that it poses well, but I don’t feel like the show has done a great job of showing us why that threat exists. I hope we will get more on that before the season ends, and I hope it will be more nuanced than a belief that artificial life is superior to biological life.

We get more nice moments for Georgiou (Michelle Yeoh) in this episode as well, including a well choreographed fight scene between Georgiou and Control-Leland (can Michelle Yeoh please fight people in every episode in which she appears?) Control-Leland initially manipulates Georgiou into doing his bidding by playing on her desire for power, arguing that Gabrielle is more powerful than she is and therefore she should be helping him bring her down.

But ultimately, she turns on him when she realizes he has been infiltrated by the AI, and we do see several shades in this episode through Yeoh’s performance of Prime Georgiou.

Tyler also initially follows Control-Leland’s orders, before turning on him. I really thought when Control-Leland stabbed Tyler that this was going to be it for the character, but at the end of the episode it is referenced that he made it into an escape pod before the Section 31 ship escaped. (Three cheers for that Klingon physiology!)

Also, I would enjoy more flirting between Georgiou and Tyler; that was fun.

Unfortunately, it’s time to talk about Sylvia Tilly (Mary Wiseman). Tilly is not being well served during the back half of this season. Since the May storyline ended in “Saints of Imperfection,” Tilly has had very little to do other than provide quick comic relief moments. However, those moments are becoming too much – even Pike and Saru this episode seemed annoyed by the inane babble.

Tilly, when done well, is an amazing character (see “Saints of Imperfection.”) But when even the characters are starting to find her a bit much, it’s time to reassess.

“Saints of Imperfection” was so good for the character because it showed us more than just one note. That’s a character I believe will go on to become a captain. The Tilly we’ve gotten in the last couple of episodes, what little we’ve gotten of her, is not.

And lastly, I’ll end by talking about Spock (Ethan Peck), because Michael is not the only person deeply impacted by the revelation of the identity of Gabrielle. Spock has been seeing Gabrielle most of his life, to the point that it drove him partially insane. According to Gabrielle, the combination of his Vulcan and human genes, as well as his dyslexia, allowed him the ability to process and accept Gabrielle’s appearances in a way that others would not be able to.

The last scene in Michael’s quarters with Spock, in which he rekindles her hope by reminding her that the future is not fixed, is sublime. “Now does matter,” he tells her. “What happened before no longer exists. What will happen next has not yet been written. We have only now. That is our greatest advantage. What we do now, here, in this moment, has the power to determine the future. Instinct and logic together. That is how we will defeat Control in the battle to come.”

We’re in the endgame now for Star Trek: Discovery Season 2, and according to the cast at PaleyFest last weekend, the ending to this season is going to be a gamechanger. I have my suspicions about where things are leading – that range from the tame to the insane – but there is still a lot of story to get through in the season’s last three episodes.

I think we are going to need to buckle up!

That’s it for “Perpetual Infinity,” now it’s time for your take on this week’s episode! Share your thoughts in the comments below, and then watch for more updates on the next episode of Star Trek: Discovery as we approach next Thursday.