Synopsis：Erin, a down-and-out street vendor, is cruelly betrayed by her fiancé and best friend, yet no one knows she is actually the long-lost princess. Just as the three princes uncover the truth and prepare to bring her back to the royal family, her best friend steps forward and falsely claims the princess identity. In the dangerous trials that follow, Prince Charles repeatedly risks his life to protect Erin as his “sister,” and Erin slowly develops forbidden feelings for her “brother” Charles.