You might laugh a little and cry a lot, but don’t think this movie will make you ponder too deeply about illegal immigration. Though “Under the Same Moon,” directed by Patricia Riggen, does a lot of talking about the subject, the heart of this film is about the separation and reunion of a boy and his mother.

The opening scene presents Carlitos (Adrian Alonso) and Rosario (Kate del Casillo), waking up to the sounds of their alarms. For a second it’s as if they are waking up together, but it soon becomes clear they could not be further apart. The film wastes no time laying it on thick when Carlitos and Rosario share their weekly telephone call via pay-phone. And once the waterworks start pouring from the adorably chubby 9-year-old, we are pulled into a film that just won’t let us go.

We soon find out that four years earlier Rosario swam across the border with a friend, who she now lives with in Los Angeles. She sends money to her son in Mexico each month, but she questions whether the separation is worth what it can buy. Carlitos works with a woman selling passage across the border, longing for the day when he’ll be with his mom again.

Fortunately for Carlitos, a Mexican-American college student named Marta (“Ugly Betty”’s America Ferrera) walks in with her brother offering to take babies across the border for cash. Carlitos’ boss dismisses her, retorting that she doesn’t even speak Spanish. However, Carlitos remembers this offer after his grandmother unexpectedly dies. When he decides it’s time to take matters into his own hands, he makes his way across the border with Marta, hiding in a hole carved out of the backseat.

With the help of strangers, Carlitos begins a journey that must ultimately end on Sunday, before his mother calls and begins to worry. Another undocumented immigrant, Enrique (Eugenio Derbez), who is at first disgruntled by Carlitos’ helplessness, finds compassion in his heart and gives Carlitos the strength he needs to forge on despite his struggles. Meanwhile, Rosario finds herself questioning whether she should go back to Mexico or marry Chito (Isaac Bravo), a legal citizen she clearly does not love, but who could offer her the security she needs.

Though “Under the Same Moon” struggles to be more, it is ultimately only successful at pulling on the heart strings. At times it strays into the arena of melodrama, but the realistic subject matter prevents it from being overly sentimental.

The film’s main problem lies in its treatment of the issue of illegal immigration. The plot is altogether too contrived, and its depictions of Mexicans and Americans are too stereotypical. How unfortunate that the film is all emotion and no relevance, considering how pertinent the subject matter is at this time.

Luckily, these contrivances are mostly overshadowed by the earnest performances given by Alonso and Casillo. Alonso shines brightly as the spirited and sincere child whose only goal is to make his way to his mother. We are on his side from the start, and he exudes so much energy it does not seem like much of a stretch for him to cross the hundreds of miles from El Paso to Los Angeles. The very beautiful Casillo also gives a performance that evokes the pain of a mother separated from her child. She remains reserved, as if a whole piece of her life is gone while parted from Carlitos.

Though the film never manages to supersede convention, particularly when dealing with illegal immigration, it is difficult not to bask in Carlito’s and Rosario’s joy when they are finally reunited. Just expect to shed a tear or two.