Helena Kapodistrias is a character in 80 Days. She is an artificer with a unique invention in her possession, and her storyline is part of the Portal to the Past achievement, as well as the Spend a Night in Machu Picchu achievement.
Passepartout first meets Helena whilst exploring the great Library in Alexandria. There he finds her experimenting with a quartz projector which harnesses "old light" stored within the physical world, effectively allowing the user to see into the past.
Continuing on the Cairo, Passepartout will run into Helena again. She will ask Passepartout to accompany her aboard the Nile Express to Luxor to conduct further experiments. The three stay in a hotel in Luxor but the next morning Passepartout and Fogg find she had mysteriously vanished. Stranger still, she has arranged for the projector to be with their suitcases.
By using the projector in Helena's room, Passepartout and Fogg are able to witness her abduction, and learn that she has been taken aboard an airship to Manama. The two give chase aboard the same airship and, again using the projector, locate Helena in the ship's engine room.
Arriving in Manama safely, Helena decides to return to Alexandria to keep developing her machine, but assists Passepartout and Fogg in finding speedy passage to Karachi.