Elpis Greek for Hope but it's history and the owner's is something else. Elpis is indeed a house with high security so you have to knock. Even if you do knock you have to have an Eidos kid/adult with you. Long ago, a Son of Demeter, Lámpsi Eidos asked Hephaestus for his blessing so that he may be able to build Elpis. "So that many others in the future may rest" He said. So he spent most his whole life, building, perfecting the house. When he was done he dedicated it to Hephaestus. So in Elpis, there are many hidden rooms and hidden security, defense, and offense forces that are to be kept in secret.
The owner of Elpis,Lámpsi Eidos originally build Elpis for a place of rest and peace with no violence but when you have a family full of heroes,villains,and spies then they tend to mess stuff up so now every room either has a hidden door or a weapon under the bed.-_-
So every room has its own theme to it, it may be modern or it may be Victorian. Elpis is full of surprises.