Sub-plots contain all the same elements as the main plot--character, conflict and resolution. Although it used to be common to see sub-plots functioning only as comic relief, with little connection to the rest of the story, they now are expected to parallel and advance the main plot. Sub-plots involve secondary characters interacting with the protagonist or the antagonist. One of the sub-plots of Gladiator, for example, is the love story between Maximus and Commodus' sister, Lucilla. The romance has a beginning, middle and end just like the main story, but takes up very little screen time. Because Lucilla becomes involved in Maximus' attempts to overthrow her brother, the love story has a direct effect on the main plot. However, it does not overwhelm it.