Family feeling runs deep in Hampstead Theatre's new three-hander, Sunday Father. The title refers to the type of father Jed had as a child and is in danger of becoming - a shadowy figure who, having left the family home, sees his son only once a week. But Jed is into more hands-on parenting than his own dad and struggles with his changing role in the life of the (never seen) four-year-old Daniel, as well as with his unfaithful wife Amy.

Paternal title aside, however, it's the filial bond - between sportswriter Jed and his older brother Alan, an unhappy junior lawyer in their aging father's firm - that's more evident. You don't have to witness Alan's second-half Cain and Abel storytelling to identify the conflicting emotions of loyalty and jealousy that distinguish this sibling rivalry. And, knowing that the play's world premiere in Toronto earlier this year starred the Canadian playwright Adam Pettle's brother, Jordan, packs this plot strand with an extra (suspiciously auto-biographical) emotional punch.

Here, in Rupert Goold's European premiere production, it falls to Dan Fredenburgh, as a sensitive if at times irresponsible Jed, and Corey Johnson, as an embittered and energetic Alan, to capture the brother's uneasy relationship, and both play their parts ably.

As adulteress Amy, Raquel Cassidy is also beguiling, though she's let down by the contradictions in Pettle's unsympathetic characterisation. A psychologist, Amy displays an astonishing lack of self-awareness, responding with a refrain of "I don't know" whenever asked to explain her increasingly bizarre actions.

There are other frustrations in Pettle's script. While abundant North American, baseball and Yiddish references anchor the piece, they may at times perplex non-Jewish Londoners, despite the programme's in-depth glossary. In either culture, the addition of Greek mythology to the mix seems at least one ingredient too many.

Even more awkward are the numerous audio flashbacks, with two boys voicing Alan and Jed as children. As scene transitions, these slow the pace and leave the visible actors twiddling their thumbs. It's unclear whether the device is a script diktat or a directorial decision - either way, it would be much more satisfying, both visually and symbolically, to have Fredenburgh and Johnson act out the episodes.

Perhaps that extra onstage interaction would also give the Jed-Alan conflict a necessary boost. As it is, the custody battle and the brotherly one seem to compete between themselves, with neither the clear winner, to the dramatic detriment of both.

- Terri Paddock