Doors to Elsewhere - Heart: The City Beneath

Doors to Elsewhere - Heart: The City Beneath - Rules of Play says:

As dozens of doors to a strange land between dimensions begin to open throughout the Heart, the delvers step through to find the city of Elsewhere in turmoil. The lights which keep them safe are going out one by one. An ocean of vicious darkness roils at the edge of Elsewhere and seeps through to the City Beneath. Will the delvers save this nexus of worlds? Inside you’ll find:

• A campaign frame designed to pull characters into the City Elsewhere
• Places to go and people to see in this land between worlds
• Rules for surviving the city at night
• Details on major and minor dimensional links through Elsewhere
• Spells specific to the culture of Elsewhere, such as Summon Bridge