Welcome to Valhalla

The last thought Charlotte had was death.
She remembered her final fight the the primordial deity, Erebus, but everything else was vague.
She remembered her friends: Char, Liam, and Mason, and she remembered who she was, but she had no idea how she was still alive.
When Charlotte finds herself in Hotel Valhalla, a place of myth, she becomes determined to get out and save her camp from Erebus, but an unexpected demigod enters her path which makes her doubt her choices.
Will she be able to defy death and save Camp Jupiter from an enemy with an unknown motive before it is too late?