After a mishap in a magic duel, the ponies are transported to the Team Fortress universe. They'll take the classes places while The Engineer tries to find a way to get them home.

Nightmare Moon has won, and the world has been shrouded in eternal night. But hope still lives. The land of Equestria is currently divided between the armies of the usurper and those of the Dawn Militia. However, the greatest danger to the rebellion may not be the dreaded Mare of the Moon, but her lieutenant, Eclipse–formerly known as Twilight Sparkle.

Hope is the faith of the young. Losing everything she holds dear, Puppysmiles embarks on the adventure of her life to find her mother, her hopes of meeting her again driving her through the horrors of a world not of her making. Too bad the Wastelands doesn't care about hope.

Harry Potter was a lonely boy who one day wished for a friend. Luna, trapped on the moon, wished for the same. And so their wishes are granted. How will the two deal with each other? And what about Nightmare Moon? Needless to say, their lives are going to change in both expected and unexpected ways...

Other stories in the Lonelyverse:
Hooves, Plush, and Magic: The Untold Tales
The Wizard and the Lonely Princess: Hallowe'en Special
A Nightmare Christmas

Chapters 9-11 now re-written.

The Princesses find an alien creature barely clinging to life at the scene of a terrifying crash. Can the Combined Power of the Elements of Harmony save it, or more importantly, should they save it? Will the arrival of this strange creature tear Equestria apart?

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https://tvtropes.org/pmwiki/pmwiki.php/FanFic/Article2