Low Tide ★★★

It can be hard to recognize when a life-defining moment falls into your lap, especially when you’re still just a scrawny teenager who feels like he’s watching the world go by from the sidelines. As desperate as we are to grow up, people seldom clock the moment they start coming of age. Peter (Jaeden Martell) doesn’t have that problem. When this frustrated kid stumbles upon a bag full of $100,000 in buried treasure, he can practically hear the starting gun ringing in his ears.

Growing up on the Jersey Shore, Peter and his better-developed older brother Alan (“Alita” hunk Keean Johnson) haven’t really been able to appreciate the romantic allure that brings wealthy tourists to their blue-collar hometown. But a small fortune in gold coins has a way of altering your perspective in a hurry. This will be their one magic summer. This will be the year when everything changed. This will be the season when these two boys decide what kind of men they want to be. “This is your origin story,” Sergeant Kent (Shea Whigam) tells Alan, unaware that the juvenile delinquent sitting across from him is hiding a huge secret. “Are you going to grow up to be the good guy, or the bad guy?”

A sharp coming-of-age crime saga that hardens “The Goonies” with the kind of salt-of-the-earth survivalism that bled through “The Treasure of the Sierra Madre,” Kevin McMullin’s Amblin-inflected “Low Tide” couldn’t make its stakes any clearer. The movie’s shrewd first scene, in which a group of masked ruffians break into a beachside mansion, explicitly defines the moral dilemma that will hang over the rest of this 87-minute calling card.