The plot: photo-journalist Calver (Scoot McNairy) is forced to escort his editor's daughter Sam (Whitney Able) across Mexico back to the U.S. border after she is caught up in an airstrike. Their journey takes them alongside and eventually through the Infected Zone where, thanks to a NASA re-entry failure six years earlier, there be monsters.
Calver and Sam are three dimensional characters: Calver has to make a living but is ill at ease photographing tragedy. He's a complete failure at relationships and is in touch with his son but is not allowed to be his father. Sam is from another world, the rich editor's daughter who turns out to be made of stronger stuff than your average heiress - she speaks perfect Spanish, is able to make friends and put locals at ease while Calver rubs them up the wrong way, and seems to take the situations in her stride including Calver's drunken antics that leave them stranded at the seaport. She's engaged but is there perhaps a little ambivalence? Calver clearly resents the class divide between them as well as his unsolicited babysitting role. He sees Sam initially as some kind of rich wastrel, asking her "Do you work?" a question she never answers.
Calver and Sam's relationship develops - believably - as their journey takes them to stranger places, but this is no Hollywood love affair - they are brought together not by love at first sight, nor by Calver's inept flirting, but as the witnesses of awesome and terrible sights. There's a war of the genres going on here with post-apocalyptic sci-fi, survival horror and even political satire showing their heads from time to time, but it's the road movie and quirky indie romance that carry the day.
Monsters is a sensitive film with a lot of intimate hand-held camerawork and equally intimate performances. It's also very traditional in some ways: there's no camcorder or mocumentary formatting, and overt special effects are minimal while much of the backstory is told through the signposts and ruined helicopters in the background. Visually it's gorgeous, making the most of Mexican landscapes, rivers, sunsets and the occasional ziggurat. The Monsters themselves (that is of course, assuming the title refers to the aliens) are presented as creatures of both horror and beauty.