Brothers always watch each other's backs, as shown in the first trailer for "Kin."

The sci-fi adventure film focuses on a recently released ex-con (Jack Reynor) and his adopted teen brother (Myles Truitt). The latter discovers a mysterious alien weapon capable of causing massive damage and uses it to help his brother out of a jam with a shady criminal (James Franco). This forces them to go on the run from the criminal's gang, from law enforcement, and from the original owners of that weapon.

"Kin" feels like a bit of a throwback, which perhaps shouldn't be a surprise since it was produced by "Stranger Things" producer Shawn Levy. And like the Netflix supernatural drama, "Kin" comes from director siblings Jonathan and Josh Baker.

The movie also stars Dennis Quaid as the brothers' dad, Zoe Kravitz as a friend along for the ride, and Carrie Coon. It opens in theaters August 31.