Beautiful and intelligent, Bong Soon (Yoon So Hee) is nearly perfect, except she's a cyborg! And on top of that, she has a peculiar fail-safe built into her system—one that causes her to shut down as soon as love stirs in her cybernetic heart. But despite this design flaw, Kim Joo Sung (Cho Kyu Hyun), a whiz programmer, sets out to write the ultimate code for romance.