Synchronic (2019)

Steve, a womanizing New Orleans paramedic, and his devoted partner, Dennis, face a string of deaths 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 teenage daughter, Brianna, vanishes. His marriage collapses and he misjudges Steve, whose declining health and painkiller use he mistakes for drug addiction. Their conflict turns into a physical fight.

Fueled by his diagnosis and a desire to find Brianna, Steve experiments with Synchronic. He witnesses Louisiana's past, escaping 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 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. They review Steve's time-travel footage and go to the cemetery where Steve's family is buried. From there, they journey back to the park.

Within the chaos of the Battle of New Orleans, Steve 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 symbol found there in the present.

Dennis embraces a safely returned Brianna, as Steve's spectral form lingers. Dennis and Steve acknowledge each other. The film ends on a close-up of their hands clasped together.