PENDLETON — There’s a mystery happening beneath the streets of Pendleton, and it’s up to the guests to solve it — before the police arrive.

The Pendleton Underground is planning a Pumpkin Palooza Mystery Party for Saturday, Oct. 30, from 6:30-9:30 p.m. in the Shamrock Card Room.

The evening is for ages 21 and older and includes appetizers, dinner, dessert and one alcoholic beverage. A no-host bar will also be available.

Attendance is limited to 45 people. Tickets are $75 and must be purchased by Oct. 23 to ensure enough time to assign everyone a character. For reservations, call 541-276-0730.

Yes — attendees come dressed in costume and take on the persona of someone else for the evening.

“It’s a blast. You get to not be yourself for an evening,” said Brooke Armstrong, the Underground’s executive director.

Here is the plot for the mystery:

“Skull Manor is an old estate in the heart of Spider City known for its captivating architecture, mysterious ambiance and unspeakable history. The townspeople have been scurrying about the streets to get ready for the big night of great food, inspiring conversations and, of course, outrageous gossip. This has been a daunting year of dissension and discord among many of the residents of Spider City. Rumors of blackmail, thievery, and outrageous controversies have been circulating throughout the town’s grapevines. We all hope everybody can put aside their differences for a night of fun. If not, there may be misfortune on the horizon. This is where your story begins.”

This is the first Halloween mystery at the Underground. Looking ahead, a murder mystery in a speakeasy is planned for New Year’s Eve, and in February there will be a masquerade.

Judith Burger, who is host of the mystery, said everyone really gets into character for these events.

“People take on a persona,” she said. “Introverts have as much — if not more fun — as extroverts.”

For updates, check the Pendleton Underground’s Facebook page.

Saturday, Oct. 30

6:30-9:30 p.m.

Pendleton Underground’s Shamrock Card Room

Ages 21 and older

RSVP by Oct. 23 by calling 541-276-0730