It’s a busy week for unscreened films nipping into theaters under cover of darkness. We’ve got the college comedy “HairBrained” (PG-13) concerning a 14-year-old genius who fails to get into Harvard and becomes a misfit at Whittman College, the 37th-best small liberal arts college on the East Coast. Alex Wolff plays the frizzy-maned whiz kid; Brendan Fraser is his dunderheaded 41-year-old buddy. (Eden Prairie.) In the romance “Hidden Moon” (unrated), a mysterious woman shows up at a tycoon’s funeral and his shocked family wants to know why. Wes Bentley (“The Hunger Games”) plays one of the inquiring parties. (Mall of America.) “The Saratov Approach” (PG-13) dramatizes the true story of two Mormon missionaries who were kidnapped in Russia in 1998. (Oakdale 20.) And the Spanish-language adventure “South of Innocence” (unrated) follows two brothers and a female photographer who leave everything behind after a chance meeting at a party. (Mall of America.) Proceed with caution.