If you think it rains a lot in London and Alice Springs, or so say the characters in Cygnet Theatre Company’s current “When the Rain Stops Falling,” you should see what’s happening in Pakistan and Bangladesh. In fact, the whole world’s pretty much fixing to drown in Andrew Bovell’s melancholic, grisly play about the fates of two families four generations and half a globe apart. Suicide, accidents, miracles from the sky, children gone missing and lots of fish soup precede a revelation about a grotesque father-son relationship, with Bovell making it abundantly clear that the play’s horrors touch far more people than those in his vicinity. Bovell’s material here is head-spinningly, cringingly thick, though no more so than the thunderhead of sadness and regret he seeds. Add Cygnet’s tradition of technical expertise, and the cast’s culture of ensemble takes it from there. This Rob Lutfy-helmed entry is a pretty fair abstract, especially if you can get past Bovell’s unending trail of self-indulgences. Things start miraculously enough, with a fresh fish dropping at Gabriel York’s feet out of a sodden sky above the Alice Springs, Australia of 2039. Ironically, it’s lunchtime, and Gabriel was wondering what to serve his son, whom he hasn’t seen since the boy was 7 (the year Gabriel abandoned his family). But this fresh fish isn’t just any stinkin’ ol’ fresh fish. It foretells the end of the world, predicted 80 years earlier by Gabriel’s granddad Henry Law (Adrian Alita), who said such a phenomenon would accompany a life-ending flood. Decades of interconnected stories swirl through the attempts by Gabriel Law (Henry’s son, played by Josh Odsess-Rubin) to solve the mystery of Henry’s disappearance – people and events roll by like the interminable rainstorms, with the York and Law ancestry unable to light into the normalcy that marks the perception of right living. Bovell breaks the cycle of emotional bankruptcy at the very beginning of the show, with York’s (also Alita) monologue setting us up for the spontaneity and funny character references we hope to expect. Bovell’s sympathies for those caught in the crossfire are deftly scripted, and there’s a downright seamless legato to the motley voices and characters’ movements. Even so, the story is unfairly protracted amid what by now is a sadly familiar litany of sins throughout the globe. We already know that the world can be a desperately murky place, with its apathies and its sociopolitical malfeasance. We already know that families are some of the worst offenders and that their flaws magnify in the face of dual bloodlines. As eye-catching as Lutfy’s staging and creation of ensemble culture may be, it’s competing with Bovell’s booming screed on the end of humanity writ large. The glimmer of hope for mankind, seem at play’s end, serves as the referent we’d been looking for – by then, we can’t hear it for the gloom and doom in our ears. Rachael VanWormer and Rosina Reynolds are splendid as the younger and older Gabrielle Law, although both parts suffer from the dilutive effects of the character parade. Everybody else is fine, as is the burly tech effort. It’s appropriately one-note in its effect; unfortunately, the characters follow suit. The program contains a nicely designed genealogy of the families involved – but such an effort can double as a friendly acknowledgment that you’ll need some help following the players. You will, and it’s not because of the grainy hues and textures Lutfy’s chosen to portray his surfeit of gloom and doom. Bovell’s crescendoes echo up one side of the Old Town Theatre and down the other. Why command attention through a postdiluvian flood when a gentle spring shower will do? This review is based on the opening-night production of Jan. 23. ‘When the Rain Stops Falling’ runs through Feb. 14 at the Old Town Theatre, 4040 Twiggs St. in Old Town. $34 and up. (619) 337-1525, cygnettheatre.com.