“Light and Shadows,” episode seven of Star Trek: Discovery's sophomore season, will stream tonight. And StarTrek.com is here to get you ready for it with Five Highlights from "The Sound of Thunder" and a preview of “Light and Shadows.”

Change Is in the Air

Saru, recovering in sickbay, puts a hand on Dr. Culber’s shoulder and says, “Enduring something no one thought possible can be… transformative. Perhaps… perhaps in feeling less like you were, you are more like who you were meant to be become.” Saru is changing, too, anatomically. Dr. Pollard reveals that there are spikes growing in like teeth within the cartilage where his ganglia resided, and that his fear responses were being repressed. Purpose is out there, somewhere. Saru thinks he’s being guided towards it. And he is, despite losing the very thing – fear – that defined him.

The Red Angel Returns

Burnham, Tyler, and Pike try to make heads or tails of the Red Angel – what it is, whether it’s responding to problems or causing them, and its nature and motivations. Oh, and it’s capable of time incursions, per Section 31. Key to figuring things out: Spock. Just then a new signal is detected and the trio are called to the bridge. Pike heads to assume his chair, but Saru is in it and – in an amusing moment – doesn’t catch on that he should make way for the captain. Then matters grow more urgent, and personal. The signal is over Kaminar... Saru’s home world. The Ba’ul (the Kelpiens’ predator species) fear his presence and his return after 18 years away, lest he disturb the status quo ensured by the Great Balance. The changes in Saru become even more apparent as he dares to challenge Pike, with pure anger evident in his voice.


Saru reunites with his sister, Siranna, who is now a priest like their (late) father. She’s ecstatic to see him, but furious as well. His people thought he’d been taken by the Watchful Eye for asking questions he should not have asked. Siranna is surprised to meet Burnham, and is even more shocked to learn that there are hundreds of thousands of lifeforms existing beyond Kaminar.  She’s also quite pleased to learn that humans from Earth drink tea.  However, the conversation turns serious when Siranna realizes that Saru hasn’t returned for her.  When the Ba’ul begin their approach, Siranna accuses him of disturbing the Great Balance once more. “Return to the stars, Saru,” she insists. “There’s no place for you here.”

Logic Applies

The Ba’ul appear to the Discovery and her crew, and they are a formidable entity. Pike protects Saru as one of the Federation’s own, but the Ba’ul will have none of it. Before Saru is dismissed from the bridge by Pike, the Ba'ul threaten destroy his village. A determined Saru heads to the transporter room, where he’s confronted by a phaser-wielding Burnham. “This is the only way,” he argues. And then he utters the words that cut deep and convince Burnham to let Saru leave: “Would you not do the same for you own brother?” Yet ultimately, Saru surrenders himself and the Ba’ul power down their ships.

You Do Not Even Know What You Are

Burnham, with help from Tilly and Airiam, piece together the Ba'ul/Kelpien connection. The Ba’ul narrowly escaped extinction, then attacked the evolved, post-Vahar’ai Kelpiens. Thus, they consider Saru… a predator. An oily, black Ba’ul (shades of Armus) torments Saru and Siranna, explaining the truth before warning them that this knowledge will be “contained.”  Faced with danger, Saru summons heretofore unknown physical strength to save Siranna and himself.  Then, communicating with Discovery, Saru explains that there’s a new balance to be created. “I cannot prove it, but I believe this is what the signal brought us here to do.” With Siranna’s consent Saru sets about triggering Vahar’ai on all his people. The Ba’ul are set into fight mode, willing to commit genocide. The Discovery takes action, but to little avail. Enter the Red Angel, a humanoid being that saves the day. Siranna and Saru make their peace, and she returns to Kaminar to help guide their people in coexisting with the Ba’ul. Saru promises to return home to visit. Burnham confides to Saru that she must go home, too… to Vulcan.

Global Preview: “Light and Shadows”

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Global Preview "Light and Shadows"

In episode seven, Burnham goes to Vulcan in search of Spock, where she unearths surprising family secrets. While researching what is left of the Red Angel’s signal over Kaminar, Pike and Tyler end up in battle with time itself. And, Georgiou has a few tricks up her sleeve for Leland and Section 31.

CBS All Access Promo- Try It Free

Star Trek: Discovery streams exclusively on CBS All Access in the United States and is distributed concurrently by CBS Studios International on Netflix in 188 countries and in Canada on Bell Media’s Space Channel and OTT service Crave.

Star Trek: Discovery
Michael Burnham
Section 31