It sits just outside the southern end of the graveyard's eastern wall, its vaulted chamber sunk partially below the present ground level, its top so thoroughly absorbed by the earth that only a stump of masonry at the south-west corner breaks the sod. The label has stuck for nearly two centuries, yet the only confirmed friary in Glanworth is the Dominican house known as Rock Abbey, about 200 metres to the north. What survives here is more likely the lower portion of a residential tower attached to the medieval parish church, a building that was already reported in ruins as early as 1615.

The confusion over what this structure actually was has a long history. Writing around 1849, the antiquarian John Windele described it as the ruins of the old parochial church, adding, with evident surprise, that a vault beneath it was 'inhabited by some poor family'. Decades later, in 1912, a writer named Byrne could identify it only as 'vestiges' of a church or religious house, and admitted he could find no further information about it. The chamber itself measures roughly 7.75 metres north to south and 3.7 metres east to west, with a barrel vault running along the north-south axis. Inside, each side wall contains two shallow recesses covered by segmental arches, though the build-up of debris on the floor now hides all but the uppermost 30 centimetres of each one. A doorway at the eastern end of the north wall once led to a mural staircase, the kind of internal wall passage common in medieval tower construction, though it is now partly blocked. The 1842 map recorded a much larger L-shaped footprint at this location, suggesting that considerably more of the complex survived then than does today.

From the outside, the structure has been almost entirely swallowed by accumulated ground level, with the walls buried to nearly the height of the vault on several sides. The southern part of the western wall has survived by being incorporated into the graveyard boundary, while other sections have simply collapsed or been replaced by later walling. The result is a site that reveals itself in fragments, its identity still technically unresolved, its most dramatic chapter perhaps being that anonymous family sheltering in the vault sometime before 1849.