The title is more than a pronunciation pun. He may be over-enthusiastic to do the right thing, but apprentice rabbi Joshua Avod is right in finding something wrong in the way Mordecai Tinnaver is obsessed with his late wife Sadie.
While she lived, neither of them were practising, let alone Orthodox, Jews; their now-estranged son Ben has a Gentile girlfriend who, we learn, is expecting a child. Neither Sadie nor Mordecai has ever met her.
Ben thought he had agreed with his father that Sadie would move to a hospice where her pain during the terminal stages of a chronic illness could be managed through medication. But Mordecai kept her at home, wired up to oxygen cylinders and a ventilator.
Her funeral has been an Orthodox one, but it now becomes apparent that the death of a young woman across the street will deprive Mordecai of the minyen – at least ten male Jews – expected to join in the Shivah. What's more, it's now not merely late on Friday afternoon but also the eve of Yom Kippur.
There's a coup de théâtre at the end of the first act guaranteed to shake up the audience as much as the characters on stage. Derek Bond's production has a semi-realistic set by James Perkins. You could say that the characters are also semi-realistic, not quite types but not completely sentient human-beings.
All three actors are good. David Horovitch as Mordecai makes you feel the pain which has been building up over decades as his beloved, active wife crumbled into an invalid and the almost-unhealthy obsession with both what was and what might have been which this has engendered.
Ben Caplan is authentic as the alienated Ben, whose unseen but edgily discussed Maggie may be the person who will heal the rift; that's the glimmer of hope when the drama which we're watching ends.
Ilan Goodman's Joshua begins almost as a caricature but he develops the part into a young man with a genuine spiritual calling that will, in time, blend theory and practice more smoothly. At least, one hopes so.
Shiver runs at the Palace Theatre, Watford until 22 February.