Common Side Effects Season 1 Ending Explained: What Happens To Marshall & Frances

The following contains spoilers for Common Side Effects' season 1 episode 10, "Raid," now streaming on MaxCommon Side Effects' season 1 finale sets the stage for season 2 by leaving multiple characters on compelling cliffhangers. Common Side Effects is focused on the Blue Angel Mushroom, a unique form of fungai that can only be grown in specific circumstances. The mushroom is capable of healing any physical injury, even reversing death at times. Common Side Effects' main characters, Marshall and Frances, spend the season wrestling with themselves and others over how to best share this mushroom with the world.

Complicating matters are a number of external forces, such as the FBI and the pharmaceutical company Frances works at, who wish to squash out any knowledge of the mushroom before it impacts the status quo that they have taken control of in modern society. The ten-episode first season is a frequently funny and consistently cutting appraisal of the medical system in modern America, with the inherent destructive nature of greed causing a lot of problems for the cast. Here is what happens in the ending of season 1 of Common Side Effects and how it sets up season 2.

What Happens To Marshall & Frances In Common Side Effects Season 1's Ending

Marshall And Frances Are Reunited In Common Side Effects' Season 1 Finale

Marshall and Frances end Common Side Effects season 1 on the run but together, setting up their continued partnership in a potential season — as well as a possible romantic relationship. Marshall and Frances are the protagonists of Common Side Effects, former classmates who have been reunited by circumstance after the former discovers a unique kind of mushroom that can heal any injury. Although Frances initially turns on Marshall and spends the latter half of the season separated from him, Frances' conscience drives her away from Rick and back towards Marshall.

Marshall Kusso looking out at the screen and also staring at a turtle in Common Side Effects

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Marshall has also found himself struggling while on the run, repeatedly dying only to be rescued by the mushrooms' healing properties. Aware of the government efforts to find him and Hildy's own ruthless efforts to take control of the mushroom distrubution, Marshall ends the season going on the run. The shared visions caused by the mushrooms, which still haven't been fully explained, brings them together and gives them a chance to start over. The season ends with Frances holding Marshall's hand and leaning on his shoulder, hinting their bond might become romantic.

Copano's Recovery & Agent Harrington's Mysterious Mission Explained

Copano And Harrington Are Steadily Becoming Allies To Marshall

One of the running sub-plots of Common Side Effects is the investigation of DEA Agents Copano and Harrington. Although they are best friends, they increasingly become divided over the investigation into Marshall. While Harrington remains with the DEA and is folded into the FBI raid on the grow camp, Copano grows weary of the conspiracy between Reutical and the government. After discovering the camp and saving Marshall after Hildy tried to kill him, Copano is seriously injured in the raid. Harrington saves his life and later gives him a mushroom, hinting at her disillusionment with the government.

The season ends on an ambiguous note for both characters. Awakened by the mushroom, Copano is last seen in his hospital room. Given his investigation, Copano will likely continue to look into the conspiracy. Having saved Marshall and ensured he escaped the raid, Copano could be the only person with law enforcement ties that Marshall could trust. A bigger question mark is Harrington, who ends the season riding a motorbike into the desert. She's seemingly going after Marshall, although it's unclear if she means to capture him or help him.

Common Side Effects Sets Up Rick As A Bigger Villain For Season 2

Rick Could Replace Backstein As A Major Threat To Marshall And Frances

For much of Common Side Effects, Rick is established as a minor but largely comedic foil to Frances. The incompetent chief executive officer of Reutical, any danger the apathetic but human Rick posed paled in comparison to the more ruthless Reutical board member Jonas Backstein. However, Backstein's terminal disease leads him to ingest too many mushrooms, leaving him in a comatose state while his mind is tormented by visions of the white creatures and grotesque body horror, effectively removing him from the active plot. By contrast, Rick's efforts to work with Frances drive her right back to Marshall.

Rick is positioned to carry on Common Side Effects' societal satire of big pharma, but could step into a more dangerous role if the additive spreads too far through the public.

However, his work with her and the mushroom has led to its refinement into a food additive. The additive is shown to quickly become a success, earning Rick a major win. However, it's possible that the additive will still have the mind-altering qualities of their earlier efforts to recreate the mushroom in pill form, setting up a lot of chaos in season 2. Rick is positioned to carry on Common Side Effects' societal satire of big pharma, but could step into a more dangerous role if the additive spreads too far through the public.

What Is Hildy Planning In Common Side Effects?

Hildy Might Be Common Side Effects' Most Dangerous Wildcard

Another antagonist hiding in plain sight for much of Common Side Effects is Hildy. Marshall's former teacher, Hildy is introduced as a kooky but intelligent woman who helped guide Marshall to his current state. However, her desire to control the flow of the mushroom and her belief that the mushrooms "want" her to act on their behalf has made her ruthless. She's tried to kill Marshall multiple times (only failing the last time because of Copano) and is more than happy to leave her followers behind for her own sake. Similar to Rick, Hildy ends the season with a victory.

Hildy is last seen dumping some of the mushroom concentrate into a water tower, either for storage or to potentially affect an entire town who drinks from that water. Hildy's true motivations remain a mystery, as the show has presented her as someone with grander schemes for the world at large but who is also willing to sell the miracle cure as a psychedelic drug. Hildy and her true goals is one of the big mysteries of Common Side Effects, as she could become more than just a dark example of how human greed can turn good intentions foul.

What Happens To The Rest Of Common Side Effects' Supporting Cast?

Common Side Effects' Supporting Cast Are Set Up For A Dangerous Season 2

Common Side Effects has a large supporting cast who are also largely revisited in the final moments of the first season, setting up their prospective roles in a potential season 2. Frances' former colleague Kiki has has remained alongside Rick, seemingly taking her place as his primary partner. Zane's efforts to get more unique turtles like Socrates succeeds, making him one of the only people with a crucial aspect of the mushroom's growth process. While Backstein has been removed from the action, his allies in the conspiracy, like Cecily are still actively hunting Marshall.

Ameila could become one of Common Side Effects' most important characters...

Amelia and her son Wyatt avoided arrest at the police raid, potentially giving them a chance to avoid legal consequences but forcing them on the run. Ameila could become one of Common Side Effects' most important characters, as her divided loyalty between Marshall and Hildy could become a major beat in season 2. There's also the mystery surrounding the Humanoids and their true impact on people, which has been shown to break some people's minds. The true nature of these creatures remains one of the show's biggest mysteries.

The Real Meaning Of Common Side Effects Season 1's Ending

Empathy Needs To Remain Key To The Human Experience, Regardless Of The Medical Marvels In The World

Common Side Effects ends season 1 in an interesting place, but with a clear moral beat that underscores the importance of restraint and empathy in the world of medicine and science. Many of the villains in Common Side Effects are the people who see the Blue Angel Mushroom as way to save themselves or gain power. The upper-echelons of law enforcement and pharmaceutical businesses seek to destroy the cure, as it threatens their control over society. These actions get people killed and cause a lot of unintended destruction and pain.

However, the show also rewards those who find empathy. Copano saves Marshall, and is in turn saved by Harrington. Ameila is seen protecting her son instead of prioritizing herself, leading to the reveal that she has escaped the authorities. Frances' redemption is dependent on her finding Marshall and coming around to his belief that the Blue Angel needs to be shared with the world instead of horded. Common Side Effects highlights the vital importance of humanity amid discovery even as it sets up several conflicts for a potential season 2 to resolve.