The narrow path is a spiritual tunnel that spirits have to cross through to get to the between-place, before ultimately finding peace on the other side.
Although not actually seen, the narrow path is crossed by Suzanne Blanchet when she is summoned and sent back by Thea Harman. Notably, it is referenced in the summoning and sending-back spells through the words of "Through the narrow path, I call/send you back".
Having died of hypothermia from falling into an icy stream, Gillian Lennox's spirit crosses the narrow path before ending up in the between-place. When she chooses to return to life, she crosses back through the narrow path with, unbeknownst to Gillian at the time, her cousin Gary Fargeon.
When Thea completes the sending-back spell, the narrow path manifests as a "cone" of light from the balefire that returns Suzanne Blanchet to the other side (implied to actually be the between-place). However, in Dark Angel, the narrow path appears to be more of a tunnel that the spirit crosses before being taken to the between-place. The difference is likely because in the former case, the narrow path is being invoked through the use of a spell.
- The narrow path, along with the between-place and the other side, are among the few named locations in the afterlife.
- It can be assumed that every person that died has crossed the narrow path to the between-place. Assuming that Maya Hearth-Woman's statement about vampires lacking souls is true, they would be the only species not to do so.