Lethia accidentally kills her boyfriend, Edwin. While in jail, Lethia feels very painful and depressed. So, she is arranged to meet a social worker, who introduces her to the project "Lethe". This program can help a murderer forget about the past and start a new life. Lethia agrees to join. Will she start a new and happy life?郭心儀經常做同一個夢：她發現男友王凱杰有越軌行為，憤然離開！從此他們再沒有任何聯絡。後來，心儀答應新男友的求婚，竟突然暈倒……。原來心儀誤殺凱杰，被判坐牢。她在獄中內疚不已，不思飲食，於是被安排會見社工。社工告知心儀政府有一個新計劃，該項計劃可幫助她抹去殺了男友的記憶，她也將會忘掉所有殺人後的事情。心儀決定……
