Sarah Gavron's Rocks will compete for the Golden Shell Photo: Courtesy of San Sebastian Film Festival
The film, written by Theresa Ikoko and Claire Wilson, tells the story of a young girl who is determined to keep the fact that there mother has left her and her younger brother alone from the authorities, through fear of being separated from him.
Also joining the line-up is the second feature by Brazilian filmmaker Paxton Winters. Pacified, set in the favelas of Rio and produced by Darren Aronofsky, tells the story of a friendship that develops between a girl trying to get her mum out of trouble and an ex-convict trying to stick to the straight and narrow.
More established filmmakers include Alice Wincour, who brings her third film Proxima, starring Eva Green and Matt Dillon, about a female astronaut who finds the demands of work take their toll on her single-mum relationship with her young daughter. Relationships are also at the heart of Lhamo and Skalbe, the fourth feature by Tibetan filmmaker Sonthar Gyal, which charts the story of a couple whose past prevents them getting married.
Rounding out the additions to the competition are Mug director Malgorzata Szumowska's latest drama The Other Lamb, about a young girl who begins to question her place in the religious community she was born into and the feature debut of playwright and actor Gonçalo Waddington. His film Patrick, recounts the tale of an adolescent who was kidnapped as a child.
The latest batch of films take the number of competition titles at the festival - which runs from September 20 to 28 to 17 and completes the contenders for the Golden Shell.