More than a decade has passed since the Great East Japan Earthquake and there are still around 2,500 people listed as missing: presumed victims whose bodies were never recovered, leaving them suspended in time. For those they left behind, it can be hard to move on. How do you mourn someone who isn’t officially dead?

That’s the quandary facing Mana (Yukino Kishii), the brittle, reserved protagonist of Ryutaro Nakagawa’s “One Day, You Will Reach the Sea.” It has been five years since her former best friend, Sumire (Minami Hamabe), disappeared while traveling along the Tohoku coast on the day of the disaster, and Mana seems to be in stasis: emotionally numb, and protecting her friend’s memory with the same jealousy that characterized their relationship.

Sumire’s ex-boyfriend, Atsushi (Yosuke Sugino), isn’t quite so devoted to the past. After clearing out the couple’s apartment, he leaves Mana in custody of Sumire’s most prized possession: the chunky, bedazzled video camera that she used to document her life, and which promises to reveal her deepest secrets.