The fourth episode of NBC's "Aquarius" highlighted the racial tension in L.A. in the 1960s and introduced the Black Panthers. NBC

In the fourth week of NBC’s new period cop drama “Aquarius,” the racial tension and antiwar sentiment of the 1960s takes center stage. The weight of the world seems to fall on David Duchovny’s character, Sam Hodiak, and this time he finally buckles under the pressure.

The newest episode begins with the fallout from Hodiak and Grace Karn (Michaela McManus) taking Emma Karn (Emma Dumont) away from her hippie compound and back to the world of uptight politician parents and no more free sex and drugs. She’s unwilling to speak to her parents, but they’re just happy to have her home. Grace informs her cheating and lying husband, Ken (Brian F. O’Byrne), that although their family is back together, their marriage is over. However, they’ll keep up appearances for the sake of his career. As a result, she’s now openly having an affair with Hodiak and even invites him to a Republican fundraiser where she tells him she loves him (accidentally within earshot of her real husband, but oh, well).

Just when Hodiak seems to finally be able to put a win in his column, he gets called to an arson murder in a predominantly black neighborhood that his racist investigating officer, Tolson, refers to as “the jungle.” It turns out Hodiak used to work the crime beat in that neighborhood years ago and thinks he knows his way around. Unfortunately, things have changed in the community now that the Black Panthers have moved in and are taking control of all aspects of their neighborhood. Rather than help Hodiak with his investigation into the arson murder, they pressure him to figure out who killed Michael Younger, a young boy who was strangled several days earlier, but the cops don’t seem interested in. Hodiak learns that Younger used to run errands for Officer Tolson and quickly suspects the racist cop of the murder.

When he finally gets a lead on the arson murderer, the suspect fleas into the Black Panther headquarters, where they tell Hodiak they’ll harbor the suspect until Tolson goes down for Younger’s murder. Hodiak tries to convince the new lieutenant, and his former partner, Cutler (Chance Kelly), to either let him interrogate Tolson or give him backup to get the suspect away from the Black Panthers. Cutler doesn’t want to jeopardize his new position and refuses due to the PR nightmare that would ensue, so he tells Hodiak to just let it go.

"Aquarius" star David Duchovny in a still from Season 1 episode 4 of the new NBC cop drama. NBC

Hodiak goes home, clearly having a bad day, only to discover his son Walt (Chris Sheffield) waiting for him. Walt’s been AWOL from Vietnam since the beginning of the series and Hodiak has spent countless hours trying to track him down. Walt reveals to his father that he was asked to run saturation bombing missions in Cambodia (outside the designated war zone) on villages with women and children. He tells his father that he plans to go the press with information he’s stolen from the military and prove that the president has been lying to the American people about the war. Hodiak is upset but can’t do anything to stop Walt.

Just as things look their worst for the detective, the next night he gets a call from Grace Karn informing him that Emma ran away again. She’s very distraught by her daughter’s actions and irrationally blames Hodiak for failing to find her in time and protect her once he did. Not a fan of failure, Hodiak gets a scary look in his eye and drives off into the night.

Meanwhile, Hodiak’s unofficial partner, Brian Shafe (Grey Damon) is hoping to use his ties to Charlie Manson (Gethin Anthony) to win the favor of a higher-level drug dealer who’s supplying the burlesque house he and Hodiak investigated last week. He tells the dealer, Jimmy Too Butano (Michael Drayer), that he knows a place to get some really great dope and agrees to take them to Manson’s place. They arrive just in time for Shafe to stop Hodiak from beating Manson to death out of sheer frustration.

Hodiak drove over to the compound in the hopes of beating Emma’s location out of him, but the stress of the last few days leads him to just whale on Manson, instead. Shafe manages to get Hodiak to go home while maintaining his cover. The episode ends with Shafe introducing Butano and Manson and the latter realizing that he owes his life to Shafe.

“Aquarius” airs Thursday nights on NBC at 9 p.m. It can also be binge-watched online at and on all partnering VOD platforms.