The film is about a group of young women who hold a party at a disused warehouse where they are violently attacked by a gang of vagrants before a malevolent, supernatural force is unleashed.

The film opens with gloomy footage of night-time Dublin and a female radio DJ talking about three girls who recently went missing in the city centre.

In the footage, a group of girls; Sienna (Kellie Blaise), Cara (Tereza Srbova), Louise (Vanessa Fahy) and Sian (Natalia Kostrzewa) are heading out for the 21st birthday of Corina (Siobhan Cullen).

Then three vagrant, violent men; Eamo (Brian Fortune), Scat (Karl Argue) and Hughie (Emmett Scanlan) break in and gatecrash the party.

Whilst Sian is being raped by Eamo, the lights go out, odd sounds emanate from the building, old televisions switch themselves on and a baby's haunting cries are heard.

A brave Cara and hysterical Louise take the camcorder around the building, and try and escape using the narrow beam of the camera's built-in light via the labyrinthine, brick basements with decrepit corridors.

It's well shot and produced with the best possible use made of its set..."[14] Golden State Haunts And Events said "The Inside is a hard, violent, visceral psychological horror, which gets into your belly, and leaves an unnerving disturbed feeling after watching it.

"[15] Cine Outsider felt "the basics of a decent if unadventurous Found Footage horror are certainly here, and as someone who still has a soft spot for the subgenre and a fondness for torch-lit sequences set in dark and crumbling basements, I really wanted to like it a lot more than I did.

The scenes where the guys terrorise the lasses is authentically intense, bringing to mind the infamous home invasion sequence from Henry: Portrait of a Serial Killer.

Even the score at this point is reminiscent of John McNaughton's essential chiller..." They added the "film could probably terrify someone with little or no experience of the modern horror genre... the first 40 minutes are its most interesting and that the lack of original ideas in its latter half seriously hampered its clearly passionate attempts to scare audiences witless.

"[7] Becky Bartlett of FrightFest said "The Inside is dull – filled with characters it is impossible to care about, flitting between psychological human chiller and unexplained, supernatural horror, with a desperately tedious screenplay, this is a confused movie with tacked on additions to compensate for a lack of focus or an interesting concept.

"[4] Anton Bitel of Little White Lies thought "The Inside offers a stale vision of inescapable entrapment that you, like these hapless partygoers, will wish would just end - and then suddenly it does, in a manner both arbitrary and unsatisfying.

"[9] Dread Central said the "'found footage' nightmare that will likely have even the most ardent fans of the subgenre legitimately debating whether the format is one of the worst things to ever happen in the world of horror.