Dan Brown's The Lost Symbol

Robert and Katherine get help from an old friend while trying to decipher the most recent clue.

Forced to split up, Langdon follows the next clue while Katherine joins Sato to find her father.

Malakh pressures Langdon and Peter to decipher the clues. Katherine, Nuñez and Sato try to regroup.

Katherine and Langdon persuade Isabel to protect herself. Peter reconnects with Leviathan members.

As Malakhs plan culminates, Peter and Langdon wrestle over the sacrifice needed to save Katherine.