While investigating a terroristic threat that goes viral online, Korean authorities discover that a suspect has recently boarded an international flight bound for the United States. When a healthy passenger on the same flight suddenly dies a gruesome death of unknown cause, panic erupts both in-flight and on the ground. With steadily decreasing fuel and international refusals to offer aid, the captain and crew will be forced to take unprecedented emergency measures in an attempt to save the lives of their passengers.
Jeong-hoon, who is looking back on his life because of his wife who committed suicide without a will, finds the meaning of happiness that his wife longed for, and visits the sea of memories where he found Geon-hee. A short but intense relationship continues with Geon-hee, who had been struggling with her daughter after divorce with her husband, and she smiles for the first time, and Jeong-hoon feels the small happiness Geon-hee gave him on his bus returning home.
Jeong-hoon, who is looking back on his life because of his wife who committed suicide without a will, finds the meaning of happiness that his wife longed for, and visits the sea of memories where he found Geon-hee. A short but intense relationship continues with Geon-hee, who had been struggling with her daughter after divorce with her husband, and she smiles for the first time, and Jeong-hoon feels the small happiness Geon-hee gave him on his bus returning home.