is one piece episode 688 filler?

Meanwhile, on Level 1 of the platform, Luffy, Ucy, Abddullah and Jeet and Law charge through the soldiers of the Donquixote Family. Just then, Luffy sees Cavendish as he states they found a short cut and are going ahead of Luffy.

The other fighters charge forward fighting the other soldiers. As Luffy and Ucy are being shot at, Kelly Funk (while using Bobby Funk's body) fights them off telling them to stay away from Straw Hat.

After Kelly reintroduces himself to Luffy he tells him he found a secret passage that will lead them to the top of the castle.