So what started this whole thing was Lady Veronica (the real one) was poisoned into a coma. Because her family was working towards getting her engaged to the Crown Prince, her father never informed anyone of Veronica's coma. The real Veronica is a conniving and scheming bish, so don't feel any pity for her.
Elena's parents successfully escape to another country. Elena's clueless girl act has Leabric fooled and she brushes it off. The Duke welcomes Elena with a fake grateful act and they immediately begin her training for becoming Veronica's replacement.
Later, Leabric informs her that Elena will get a knight to attend to her at all times. In the first loop, Elena was assigned Loreche (who's obviously working for Leabric and betrays Elena). Elena, keeping up her clueless act, asks Leabric if she can choose her knight. Leabric assumes Elena will choose Loreche so she allows it. Elena instead chooses a newbie knight named Hurelbad(Name correction pending). Everyone is, of course, shocked at this choice. Elena specifically chose Hurelbad because she knows in the future, he will become one of the greatest knights in the kingdom. When Leabric confronts her about this, Elena gives her a vapid answer saying she really liked Hurelbad's looks. Leabric is frustrated, but accepts the decision and warns Elena not to make decisions without her advice.
The Duke throws a ball for "Veronica's" debut. There, Elena runs into Len, Veronica's cousin, who bullied her in the first loop because he figured out Elena wasn't the real Veronica (because the real Veronica had a scar behind her ear). This time, Elena made a scar behind her ear, which confuses Len because he's still suspicious of her. Elena trips Len, causing a small commotion that distracts Leabric, and she takes the opportunity to slip away to find a certain noblewoman. With knowledge from the first loop, she blackmails the noblewoman to give Elena her maid, May. In the first loop, May attempted to kill the Duke to get revenge for her family, so Elena knew she would be the perfect attendant to have by her side so they can both work towards their revenge.
Yada yada yada, this story is hella long with tons of characters and that's as much as I want to type.
To make things short: Len teams up with Elena, Loreche is killed by Hurelbad, Leabric is thrown in prison, May gets her revenge, the real Veronica is beheaded, Ciel the Crown Prince is genuinely in love with Elena, and everyone is happy.