Watch The Moth Diaries full movie online Movies123. Watch The Moth Diaries 123movies online for free. The Moth Diaries 123Movies: Rebecca is a young girl who, haunted by her father’s suicide, enrolls in an elite boarding school for girls. Before long, her friendship with the popular Lucy is shattered by the arrival of a dark and mysterious new student named Ernessa, whom Rebecca suspects may be responsible for the rising body count at the school.