'The Librarians' season 3 episode 8 spoilers: Upcoming episode to feature combusting vampires and a dilemma for Cassandra

Now that season 3 of "The Librarians" are about to end, what other trials will the titular characters have to face as they struggle to maintain a semblance of order in magic-filled world, dodge the government agency that's been hot on their heels, and all this while trying to deal with their own personal issues?

The upcoming episode 8 of TNT's adventure-fantasy series features a brand new kind of threat in the form of spontaneously combusting humans. The Librarians' investigation into the matter will lead them to a vampire-run holistic spa, wherein the bloodsucking fiends have found a way to walk freely out in the sun without spontaneously turning into ashes.

However, whatever they have come up with there is obviously not working so well since vampires everywhere have been combusting into flames anyway. How will the Librarians handle this problem? And will the vampires at the holistic spa eventually find a way to stabilize their treatment? How will dealing with this problem affect the Librarians in the long run?

Meanwhile, the trailer for the next episode presents another pressing problem for Cassandra (Lindy Booth) as she is faced with the inevitable need to remove the tumor in her brain. While the doctor insists that an operation be performed right away, Cassandra refuses to heed and instead claims, "There's nothing to take care of."

While it comes as no surprise that Cassandra would refuse to remove the very thing that makes her special, how will this decision affect her duties as a Librarian going forward? What happens when she starts to deteriorate due to the tumor while on a mission with her colleagues? Will she be forced to get the tumor removed, or will it be too late by then?

With the villainous God of Chaos, Apep, still endeavoring to unleash Pure Evil into the world, the Librarians will soon be faced with a major good-versus-evil battle as the show's third season draws to its conclusion. Will the Librarians be ready when this battle finally happens, or will it catch them at their most vulnerable?

"The Librarians" season 3 episode 8 titled "And the Eternal Question" airs on Sunday, Jan. 8, at 8 p.m. EST on TNT.