Marcos (Gustavo Garzon), an existentially bored university lecturer, gets a grant to return to his birthplace to carry out biochemical research. There he meets old buddy Raul (Leo Masliah), who is now a priest. The story opens out to bring in their schooldays 20 years earlier, during Argentina’s politically active ’70s, when Raul was going out with Tamara (Victoria de Elizalde), who now lives in Paris with husband Paul (Ginger Poujoulet). The mature Tamara (Laura Melillo) returns to be with her sick mother, and Marcos unwittingly stumbles across some high-level politico-economic corruption on the part of the lab’s owners, led by Dr. Castembacher (Jean Pierre Reguerraz). In a piece in which perfs win out over plot, Garzon is satisfyingly nuanced as the disillusioned Marcos. Technically, pic’s restricted budget makes itself felt.An intelligently adult passing-of-time drama, with well-drawn characters and plenty of food for thought, Roly Santos’ feature debut, “How Silly We Are to Grow Up,” fuses an emotional-triangle tale to a less successful thriller subplot with predictably mixed results. Commercial prospects outside home territory are slim, but Santos is a talent to watch.(By JONATHAN HOLLAND for Variety)