A brilliant turn from Catrin Stewart anchors this stylish, twisty Welsh-language thriller from Euros Lyn.   In a role as complex and deftly played as Jeremy Irons’ performances in Dead Ringers, Stewart plays twin sisters plotting a murder within the labyrinthine shelves of the National Library of Wales.  After their celebrated author mother commits suicide by leaping from a window, Ana and Nan decide to kill her biographer after her final words implicate him.

As much as he patiently divulges the twins’ plan, Lyn also takes his time establishing the routine of the sisters themselves.  Although mirror images of each other in looks and clothing, subtle differences in mood and mannerisms are established and the audience slowly learns to tell them apart.  Ana appears more nervy and submissive, Nan steely and occasionally prone to anger.  Our belief in the characters is absolute, and Stewart richly deserves her festival award for best performance in a British film which has just been announced.

Sadly, the film doesn’t prove as gripping as the performance deserves.  There are several moments where the plan goes awry, or there is a revelatory plot moment, that doesn’t provoke the responses Lyn was aiming for.  It’s possible to watch The Library Suicides in a state of almost Zen enjoyment.  It’s never dull, but it never really raise the pulse in the way a thriller should.  Perhaps it’s because so much time and care is taken over the presentation and the minor character traits of the twins that we don’t have enough invested in their target Eben (Ryland Teifi), or Dan (Dyfan Dwyfor), a security guard at the museum who functions as Eben’s potential saviour and Ana’s possible love interest.

It’s also entirely possible to figure out the numerous twists.  They aren’t telegraphed as such, but when it becomes apparent that the major plot point revolves around a missing page from a diary from the year the twins were born, the pieces slot into place; occasionally before Lyn and writer Fflur Dafydd have had a chance to place all of them on the board.

Still, one can’t deny the ambition shown in the storytelling, and as a showcase for an exceptional performance and an admirable use of a limited location it can’t be faulted.  It’s very stylishly edited too.  If you watch it on those terms and don’t spend too much time picking apart the numerous plot revelations you’ll have a fine time with The Library Suicides.