“The Theory of Everything” stars Eddie Redmayne and Felicity Jones reunite for this story set in 1862 that follows a wealthy young widow and an ambitious scientist who mount a perilous hot-air balloon expedition to fly higher than anyone in history. As their ascent reveals their true selves, the unlikely pair discover things about each other. Tom Harper (“The Woman in Black: Angel of Death,” “War & Peace”) helms from a screenplay by acclaimed scribe Jack Thorne, while authenticity is a top priority on the film meaning that the two leads did many of the stunts themselves. Tom Courtenay, Vincent Perez, Anne Reid and Phoebe Fox co-star.