Adrestia Trefoil: Lacuna

In every puzzle, once a piece is missing, it will never be solved. Just like the murder case of Equity and Wisdom Yancey seven years ago. Almost all of the clues were collected, but to completely solve the case, the authorities are missing a big piece. A big piece for Prudence Yancey to find.

Time's running out, three more years and the case will go cold. Being orphaned at a young age and with no other alive relatives, Prudence needs to find the justice her parents deserved all on her own. Until an opportunity suddenly popped out out of nowhere and made her realized something.

What if she's the lacuna?