In the episode, she'll play a computer-savvy lady named Charlie whom the Winchester brothers meet while investigating Dick Roman (James Patrick Stuart), the billionaire who was taken over the by the leader of the Leviathans. Day's character is a tech in one of his companies and somehow gets mixed up in Sam and Dean's problems.
Check out these first looks at "The Girl With the Dungeons and Dragons Tattoo":
Hmm, we wonder why Charlie has a sword? Is it because she's awesome? Or, perhaps as the episode's title suggests, she may do a little D&D cosplay?
Supernatural returns with all-new episodes on Friday, April 20 on The CW. Day's episode airs a week later.