Following her previous experience with the Mara,companion Tegan finds herself having disturbing and often diverting dreams related to her experience. In a coinsidental moment the TARDIS makes a surprise visit to an open air bazaar on the planet Manussa,where this race are preparing a celebration the defeat of the Sumaran empire to which the Mara belonged. Once there Tegan again comes under the Mara's spell and begins to wreck havoc in the bazaar. Meanwhile Lon,the spoiled son of the of a local government official comes under the same spell purely out of boredom. It's now become the doctor and Nyssa's job to convince the skeptical Manussa that the Mara,understood only as a children's myth to them,is a very real and genuine threat to their society. In the the planet,and Tegan are freed from the Mara's influence and Lon meets him comeuppance.
Unlike 'Kinda' this Mara story is much more of a social satire than an abstraction. In the Manussan bazaar the Mara and the story surrounding it are constantly exploited by the local population. So much so they few even notice Tegan's,or even Lon's possession by it. Not only is it a tale of capitalism's tendency to exploit religious/spiritual beliefs to it's advantage,but also of the social chaos such a dilemma creates. A Manussan antiquarian refuses to acknowledge the Mara's reality at all even in front of his face. And even at a young age Martin Clunes portrays Lon with just the right about unawareness and haughty hubris that the character required. This is what makes him such an easy pawn for the malevolent Mara. It's also a good resolution to Tegan's experience with those Deva Lokan wind chimes in 'Kinda' as well. One of those followup stories worthy of the original by virtue of the differences.