Count Gregory is determined to learn how to harness the power of the Holy Grail, a secret known only to a few, including Queen Victoria.

The League of Darkness kidnaps Senior del Fuego, the Peruvian ambassador and Knight Templar, guardian of the Grail. When Phileas and Rebecca are sent to investigate, they too find themselves trapped in an alternate dimension by Count Gregory and his minions.

Meanwhile, evil replicas of the ambassador and the Foggs appear in London in order to trick the Queen into revealing the secret. Jules Verne quickly realizes these imposters are not his real friends, but he has a difficult time convincing anyone else of his suspicions.

Time is running out, and as Passepartout struggles to find a way to rescue the Foggs, Phileas and Rebecca prepare to make the most difficult choice of their lives.

Guest Star: Rick Overton

Viewer Tip: Passepartout plays with tools.

The Holy Grail

The suspicious Jules

The missing ship

The trapped Rebecca

The other dimension

The awful realization

 The "similar" Foggs

The imposter exposed

Making a difficult choice