La isla de los longevos, 1

The Japanese government has developed a rejuvenating drug that allows the body to return to its twenty-year-old state. The Aging Project has been launched, bringing together a group of volunteers over eighty years old on an island to study the possibility of reintegrating them into the workforce. After serving an unjust sentence of almost fifty years for the murder of his wife and son, Takirô Yabuzaki regains his youthful body and infiltrates the island to avenge his family's true killer...