The latest from the filmmaking duo of Justin Benson and Aaron Moorhead is a time-traveling mystery starring Anthony Mackie and Jamie Dornan. Set in an ever-atmospheric New Orleans, paramedics and lifelong pals Steve and Dennis (Mackie and Dornan, respectively) notice a trend in several gruesome deaths: all are linked to a new legal designer drug called Synchronic. When Dennis’s 18-year-old daughter, Brianna (Ally Ioannides), goes missing after taking it, Steve comes to find out the drug has dimensional-warping properties and the teen is trapped somewhere in the past.

Near the spot where Brianna was last seen, Steve finds an empty package of the titular drug, a legal hallucinogenic similar to the real-life, store-bought DMT. Around the same time, Steve is diagnosed with a rare and aggressive brain tumor caused by an overactive pineal gland, a diagnosis Steve keeps secret  from Dennis. The pineal gland is a mostly dormant part of the brain that psychedelic enthusiasts call the “third eye.” When under the influence of LSD or mushrooms, the pineal gland becomes active, and the theory goes that it is the missing link inhibiting humans from being able to transcend our understanding of time.

From the opening scene, it’s evident that the drug opens up time portals. Users are susceptible to anything they may encounter during their (literal) trips to the past. One guy gets stabbed through the chest by a Conquistador. A woman is bitten by a snake that is no longer native to New Orleans. But here’s the catch: adults who take Synchronic only go to the past for a brief stint (around seven minutes), but teenagers get trapped there because their pineal glands are still active. So who do we know who might be able to get Breanna, ahem, back to the future?

All of Moorhead and Benson’s films have third act problems (although in Synchronic, the problems begin in act two). Their films tackle high concepts that start out cool, but by the end the filmmakers don’t delve any further than simply setting up the trippy premise. The first act hints at a commentary on the toll of drugs and alcohol, but for Moorhead and Benson, it only serves as scene dressing for a story about one bro risking his life to save another bro’s family.

Part of the danger in traveling back in time is that Steve puts himself at risk of being lynched during Jim Crow days, or being bonded into slavery during the Battle of New Orleans, and in both cases the threat never feels imminent but more expository. (During the Jim Crow segment, he hides in bushes. If only it were that easy).

Mackie and Dornan are believable as two lifelong friends. Their characters feel very lived-in, with a natural rapport. Dennis’s wife, Tara (Katie Aselton), and daughter pop in every once in a while for the men to bounce off dialogue, but they are not around long enough to develop into anything more than one-note characters.

Moorhead and Benson’s dude-bro sci-fi style is comparable to the Don Coscarelli film John Dies at the End, which sprang out of the novel by David Wong. In John Dies, two slacker buddies come upon a drug known as “soy sauce” or “the sauce” that allows its users to see interdimensions. The two films share very similar premises, but John Dies succeeds at having fun with all the heady stuff while somehow still making sense, but Synchronic slogs its way to a predictable ending.

However, an opening sequence of one continuous shot set in a drug den is eerily played out. The ambient soundtrack and sepia tone cinematography add significantly to the tone, and screenwriter Moorhead has a penchant for writing hilarious dialogue. Lastly, Moorhead and Benson accomplish a lot with the limitations of their budget, especially with the special effects, which always look convincing.