Halloween-themed episodes of popular series often tend to resemble the holiday itself, with the characters having fun by playing, well, characters.

The British series Agatha Raisin, which routinely does a good deal of winking at its audience anyhow, has a jolly good time his year with a Halloween episode that's pure fluffy fun.

A multiple murder notwithstanding.

Conveniently positioned as the first episode of the show's third season, Agatha Raisin and The Haunted House becomes available Monday on Acorn.

Like other Agatha Raisin episodes, it's based on a mystery novel by M.C. Beaton.

As the name suggests, Agatha (Ashley Jensen, top) starts this tale by trying to figure out why a forbidding old grey stone English mansion seems to be haunted.

The early scenes, in which she and her partner James (Jamie Glover, right) prowl through the darkened mansion at night in an attempt to track ghostly sounds, give her an opportunity to act like a young teenager at a haunted house party.

Or, if you will, a young cheerleader in a slasher flick. Except that even with anguished wailing in the background, Agatha Raisin never feels anywhere near that dark.

Agatha's flaky disposition remains as bright as the colors that seem to surround her perpetually. She's a sunny optimist in a business where she is constantly required to figure out why various people turned up dead.

Here she and James enter the case before any of the aforementioned bodies turn up. Agatha has just secured her private investigator license and opened up a bright, quirky office in an old church out in the bucolic countryside, where, unfortunately, there may not be enough crime to put her services in high demand.

So when she and James see a story about Olivia Witherspoon (Richenda Carey), the woman who lives in the forbidding old grey stone mansion, they pay her a visit and offer their services as ghostbusters.  

The haughty Olivia greets them at the door with a vintage musket and doesn't get much warmer as the conversation progresses.

But they all need each other, so Olivia tells them the story. The mansion was once owned by a chap who fought on the losing side in the civil war of the 17th century, and it's said that his ghost has haunted the joint for the past 400 years.

This is relevant because he was said to have hidden a vast treasure on the property, a report that has led a steady stream of treasure hunters to poke around and try to find it.

These intrusions have gotten old for Olivia. So when the ghostly sounds escalate, she figures it must be someone trying to drive her out and get a clearer shot at the alleged treasure.

That's when Agatha and James arrive, and it turns out things get worse before they get better.

This movie-length feature also gives us battle re-enactments and small-town secrets and other colorful, amusing stuff. Agatha herself, true to form, floats around seeming a bit spacey until it matters, at which time she reverts to being an ace detective.

Hey, it's Halloween. Give that woman an extra bag of candy corn.