Synchronic is a 2019 American science fiction horror film directed and produced by Justin Benson and Aaron Moorhead. Written by Benson, the film shares continuity with other films by Benson and Moorhead, following Resolution and The Endless. Synchronic stars Anthony Mackie and Jamie Dornan as paramedics who investigate a series of inexplicable deaths and their connection to a new designer drug.

It had its world premiere at the 2019 Toronto International Film Festival. It was released on October 23, 2020, by Well Go USA Entertainment.

Steve, a womanizing New Orleans paramedic, and his devoted family-man partner, Dennis, face a string of horrifying deaths and incoherent victims – all linked to a new designer drug, Synchronic. When Steve is accidentally pricked by a contaminated needle during a call, tests reveal not only possible infection but also an aggressive cancer in his underdeveloped pineal gland.

Driven to uncover the truth about Synchronic, Steve tracks down the drug's creator. He learns it warps the pineal gland's perception of time, sending users backwards through history. Children experience full time travel, while adults exist only as ghost-like figures in the past.

Meanwhile, Dennis's world shatters when his teenage daughter, Brianna, vanishes. His marriage collapses under the strain, and he tragically misjudges Steve, whose declining health and painkiller use he mistakes for drug addiction. Their conflict erupts into a physical fight.

Fueled by his diagnosis and a desire to find Brianna, Steve experiments with Synchronic. He witnesses Louisiana's past, barely escaping deadly encounters with a conquistador and the Ku Klux Klan. Using his dog, Hawking, he discovers the location of pill consumption dictates the destination year. But in a heartbreaking turn, Hawking is lost in the 1920s, unable to return with Steve.

Steve deduces that physical contact with objects can anchor someone in a specific time. Returning to the park where Brianna disappeared, he encounters prehistoric tribesmen but learns Brianna might have simply wandered off before taking Synchronic.

Reconciling with Dennis, Steve reveals his cancer diagnosis. Joined by their colleague Tom, they review Steve's time-travel footage and rush to the cemetery where Steve's family is buried.  From there, they journey back to the fateful night in the park.

Within the chaos of the War of 1812, Steve finally locates a terrified Brianna. When a looter, mistaking Steve for a runaway slave, threatens them, Steve sacrifices himself as a distraction so Brianna can use his last pill to return to the present. Fatally injured and the looter killed by a landmine, Steve carves the word "ALLWAYS" into a boulder. This act casts him as the originator of the mysterious symbol found there in the present.

Dennis embraces a safely returned Brianna, as Steve's spectral form lingers. His journey complete, Steve bids a peaceful farewell, having gained emotional closure and a profound understanding of time's interconnectedness.

In September 2018, it was announced Jamie Dornan and Anthony Mackie had joined the cast of the film, with Justin Benson and Aaron Moorhead directing.^[3]

Synchronic shares continuity with previous films by Benson and Moorhead. It is mentioned that the titular drug was synthesized from a red flower grown in the California desert, referencing the plant smoked by members of a commune in the film The Endless.^[4]

The film had its world premiere at the Toronto International Film Festival on September 7, 2019.^[5] Shortly after, Well Go USA Entertainment acquired distribution rights to the film, announcing a 2020 release.^[6] It was released in theaters on October 23, 2020.^[7]

Synchronic was released on digital and video on demand in the United States on January 12, 2021. The movie was released on Netflix in the US on April 16, 2021.^[8]

Review aggregator website Rotten Tomatoes reports an approval rating of 79% based on 155 reviews and an average rating of 6.8/10. The site's critics consensus reads: "Synchronic sets off on an intriguingly idiosyncratic journey that should satisfy fans of Aaron Moorhead and Justin Benson's earlier work."^[9] Metacritic reports a weighted average score of 64 out of 100 based on 23 critics, indicating "generally favorable reviews".^[10]