Wikipedia: Pandora's Box...
Zeus, upset with the brothers Prometheus and Epimetheus for having successfully brought fire to humankind, making for all those annoying sparkling lights on the ground at night, decides to even things up by introducing disease, death, and sorrow to humankind. He orders Pandora to be created and gives her as a gift to Epimetheus, brother of Prometheus. Pandora and Epimetheus decided to get married. As a wedding present Zues gave her a box and told her never to open it. Curiosity got the best of her and she opened the box letting the disease, death and sorrow to humankind, which is just what Zues wanted. When Epimetheus came Pandora was in pain. The n they realized that something else was in the box knocking and asking to get out. Epimetheus told her that what more harm could be done and to open the box. When she opened the box hope came out. All her scars and diseases were cleared.
It looks like if they shy away, they lose, they have to open the box again to win.