This week on Star Trek: Discovery, Michael tries to help Sarek, Tyler joins the crew, and Admiral Cornwell issues a warning.

Last week on Star Trek: Discovery, Lorca was captured by Klingons and met Harvey Mudd and Lieutenant Ash Tyler. Discovery saved Lorca and Tyler after they escaped the Klingon ship. Also, Michael and Tilly set Ripper free, and Stamets used the spore drive tech on his own body.

“Lethe” begins with Sarek and Adjunct V’Latak leaving Vulcan on a diplomatic mission. V’Latak asks where they are going, but Sarek refuses to say.

Michael and Tilly run around the ship and try to shave seconds off of Tilly’s time. Tilly wants to be a captain someday and Michael is doing her best to support her friend and be a good mentor. With her encouragement, Tilly surges ahead.

On the holodeck, Lorca and Tyler fight in a simulation against Klingons. Lorca asks Tyler about himself, and later admits he looked over his file. He notices Tyler lies about how many more kills he made than Lorca, and tells him he wants his new security chief to be a great shot. Lorca says Tyler is a great fit as he trusts him and he fights like the Klingons.

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Sarek announces they are almost at their destination, then V’Latak injects himself with a chemical that slowly explodes. He accuses Sarek of caring too much for humans and says Vulcans are better. He says his death will be “a rallying cry” for logical Vulcans.

Back on Discovery, Tilly and Michael go to the replicators for breakfast. Michael dismisses Tilly’s original order and gets healthy breakfast burritos. Tilly notices Tyler sitting alone and shares rumors. She then goes to his table and Michael follows. Tilly introduces them to Tyler. He realizes who Michael is, but is nice and offers his hand to shake. Michael shakes it, but feels strange and collapses.

Michael sees Sarek lying on the cafeteria floor and flashes back to Vulcan and sees Amanda Grayson, Sarek’s wife arguing with Sarek on her behalf. The past Michael apologizes for not being good enough to get into the Vulcan Expeditionary Group while Amanda tries to offer comfort. Sarek says he will try to get Michael into Starfleet. Sarek then notices the present Michael and asks why she is there, attacking her and throwing her out of his mind. In a previous episode Sarek mentions he shared some katra, basically his soul, with Michael, so they have a special connection.

Michael wakes abruptly in medical to see Culber, Tilly, and Lorca. Culber says nothing appears physically wrong and Michael tells them about Sarek. She says a group of Vulcan logic extremists bombed her learning center because she is human. She was dead for three minutes and Sarek brought her back with the katra, despite it being looked down upon. Michael says she thinks Sarek is dying and asks Lorca to help find him, and he agrees.

Lorca speaks to Admiral Terral who confirms Sarek’s ship was harmed by Vulcan extremists. He mentions Sarek was chosen to go speak to a group of Klingons who want hurt Kol’s leadership. Terral says Sarek is in a nebula and Starfleet is looking at options. Lorca announces he will find Sarek, but Terral says no. Lorca ignores him and disconnects.

Discovery arrives in the nebula but cannot find the ship because of the disturbances in the nebula. Michael has an idea of how to find Sarek.

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Michael goes to Stamets, asking for tech to enhance her connection with Sarek. Stamets tells them they cannot take the ship into the nebula because of the spores, so Michael says she will take a shuttle. Michael asks for Tilly to go too, and Michael agrees but says he is sending Tyler too as pilot. The team gets ready for the journey and Lorca demands Tyler bring Michael back safely or not return at all.

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Admiral Cornwell arrives and is furious with Lorca for doing an unauthorized rescue mission. She questions his judgement on letting Michael and Tyler go and on Stamets work with the spores. He says they have to win the war. He and Cornwell calm down and have a drink. Lorca and Cornwell reminisce about the past. Cornwell says Lorca is different and is taking unnecessary risks. Lorca starts flirting and Cornwell seems receptive.

In the shuttle, Tilly encourages Michael to talk to her and Michael does. She says Sarek’s last thoughts are about her and her failure. Michael hooks up to the tech and tells Tilly no matter what to not remove her from the machine. Michael enters Sarek’s mind and sees herself and Amanda. Amanda gives her the Alice’s Adventures in Wonderland book and tells her to remember she is human. She turns and sees Sarek talking to the Vulcan Expeditionary Group director. Sarek returns to his family to tell them Michael was not accepted. Sarek and present Michael begin fighting again. Michael’s vital signs go haywire and Tyler pulls rank and makes Tilly wake her up.

Tyler wants to go back to Discovery, but Michael will not leave without Sarek. Michael tells them she is having trouble getting through to Sarek. Tyler says near death, you focus on loved ones and what you would have changed in your life. Using that information,Michael tries again.

The next time Michael goes in, she asks what he is hiding. The two fight and she asks Sarek to let her into his mind. He shows her the truth. The Vulcan Expeditionary Group director told him to pick one of his children. Neither was seen as Vulcan enough with Michael being a human and Spock being half human. Sarek chose Spock. Michael is angry he never told her because it made her feel like a failure. He says he feels shameful. He opens his mind to the connection and they both wake.

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Back on Discovery, Cornwell wakes beside Lorca and traces scares on his back. Lorca wakes and attacks her, then points a phaser in her face. She dresses and accuses him of lying on his psych evaluations. She says he is different and says he is not keeping Discovery. Lorca pleads, but Cornwell leaves. Saru calls Lorca and tells him the team has arrived with a badly injured Sarek.

In medical, Michael says Sarek will survive but cannot go meet the Klingons. Lorca notes Admiral Cornwell is near and believes she will accept the mission. Lorca compliments Michael on a job well done and she in turn thanks him for agreeing to the rescue mission. He says he did it for her and she is now the science specialist on the bridge. She accepts and goes to see Sarek. Michael asks him to talk to her, but he refuses and notes they are not really related when she calls him family. She tells him they will talk about it someday, calling him father as she leaves.

Cornwell tells Lorca she will talk to him about leaving Discovery when she returns. He nods and wishes her good luck.

Photo Cr: Ben Mark Holzberg/CBS © 2017 CBS Interactive. All Rights Reserved.

Michael meets Tilly, who is running in the hallway. Michael says there are tons of ways to become a captain, and Tilly needs to find her own. Tilly says she has and Michael smiles as she watches her continue to run down the corridor.

Michael gets some tea in the cafeteria and sits down with Tyler when he kicks out a chair. He asks about Sarek and she says he is being difficult. Michael shares she learned neither of them can be who the other wants. She shares the conflicting feelings she is having about Sarek and Tyler says that is just part of being human. Michael offers her hand and the two do introductions again.

Cornwell arrives in the neutral territory to meet with the Klingons. Cornwell introduces herself and then the Klingons attack, killing the hosts and all the Starfleet crew except for Cornwell. The Klingons call Kol and he tells them they are now welcome in his empire.

Saru tells Lorca the meeting was a trap and Lorca tells him to contact Starfleet for orders. Lorca tells him the Discovery is too important if there is another trap. Lorca turns and stares out the window, phaser gun in the back of his pants.

This episode was good, but I wish there was even more on Michael and Sarek’s relationship and background. I love seeing Michael helping Tilly work towards her goal. I am still concerned Tyler is a spy. Lorca is as unstable as I assumed and I think he sent Cornwell believing the meeting was a trap. Stamets was interesting this episode, very peppy and cheerful. I wonder if it is because of his experience with the spore drive, or if that hint of the mirror verse was more than just a hint. All in all I think this was one of the better episodes character wise.

Star Trek: Discovery releases new episodes Sunday nights at 8:30 p.m. on CBS All Access in the USA. Canadians can watch on Sundays at 8 p.m. on Space, and various countries can watch Mondays on Netflix.

Check out the preview for the next episode of Star Trek: Discovery below.