In their latest film, Jimmy Chin and Elizabeth Chai Vasarhelyi continue to pursue their fascination with the lengths to which a human body can be pushed, and the strength of spirit required to push it there. After following up their Oscar-winning documentary Free Solo with a dip into the untested waters of narrative filmmaking in Nyad, they’ve returned to the nonfiction realm to tell the dual story of Ernest Shackleton’s 1914 Antarctic expedition and the quest, over 100 years later, to locate the wreckage from the voyage. But while Endurance continues the thematic through line of Chin and Vasarhelyi’s previous films, and while some of the photography is as impressive as the stomach-churning cliffs of Free Solo, it never manages to delve into the deeper psychological layers that made that film so compelling.

Directed by Chin and Vasarhelyi along with Natalie Hewit, Endurance moves back and forth between the two voyages throughout its runtime.