The Makropulos Case is not an easy opera to classify. Karel Capek who wrote the play on which Janacek’s work is based called it a comedy, but it becomes a meditation on life and death, specifically on extreme longevity, and ends in a scene which can be seen as tragic. A programme article is headed, “From Universal Comedy to Personal Tragedy” – overstating the case a touch, I feel, but evidence of the contradictions of tone implicit in the opera.

The plot begins in legalistic fact and spins gradually into metaphysical fantasy whilst the settings and most of the characters remain rooted in 1920s reality. A court case about an inheritance dating back to a 100-year-old will has just finished when Emilia Marty, the current sensation of the opera and a woman of mystery, appears in the lawyer’s office alarmingly well informed about the maker of the will. She proves to have lived and remained youthful for over 300 years. The Makropulos case is solved, but that’s not what the opera is all about!

Tom Cairns’ intelligent production seems a touch stolid at first, but develops momentum and a sense of fantasy and is certainly a clearer narrative than some productions of The Makropulos Case which focus more on E.M. as a star turn. If you require E.M. to be “mesmeric” and “magnetic” at first sight, as George Hall describes Anja Silja in the part, then Ylva Kihlberg is not for you. There is no great magic in her first act performance, but thereafter the characterisation (the mystery, the allure, even the sense of humour) develops and she sings with increasing freedom and power.

A strong and well balanced ensemble sings uniformly well and generally succeeds in fleshing out somewhat sketchy characters. Nigel Robson makes much of the one “gift” part, the dotty ageing roué Count Henk-Sendorf, E.M.’s lover in one of her earlier incarnations. Robert Hayward unbuttons, metaphorically and literally, as the overbearing, but tormented, Baron Prus, and as his adversary Albert Gregor no one is better at presenting an existential nightmare than Paul Nilon. James Creswell and Mark Le Brocq are an admirable legal duo and Cairns finds the humour in some of the smaller parts, notably Stephanie Corley’s star-struck young opera singer and Rebecca Afonwy-Jones’ mindlessly loquacious chambermaid.

But ultimately the evening is all about Richard Farnes and the orchestra. Much of Janacek’s most thrilling music lies in the orchestra, the end-of-act climaxes instrumental rather than vocal, and this is a stunning performance, exciting, dramatic, beautifully paced and full of telling detail.

Opera North’s The Makropulos Case runs at Leeds Grand Theatre until 2 November.