Forty-five years separate the two acts of At Home at the Zoo, though in terms of the play’s action it’s probably only an hour. The second act is The Zoo Story. Written in 1958, it’s the play that assured Edward Albee’s genius. The first act is Homelife, written in 2004 as an exploration of what happened earlier in the older play.

I wish he’d left it alone.

The chief joy of seeing At Home at the Zoo, presented at Arena Stage as part of the Edward Albee Festival, is that second act. Featuring a lightning rod performance by James McMenamin as the mysterious Jerry, it’s a speedy and dangerous duel between action and reaction as he plays off the controlled listening of Jeff Allin’s erudite Peter. The entire stage comes alive with this act, a true evocation of why Albee is still revered today as one of our greatest playwrights.

But you have to get through the first act. I recommend caffeine. If you can make it through without your eyelids drooping too much, your energy will be revived by the tension of a riveting second act. Don’t give up. It’s worth it.

Peter (Jeff Allin) and Ann (Colleen Delany) live in an airless all-white world of tea and sympathy. Their placid, boring surface, we learn, hides the darker underbelly of Ann’s desire for more meaningful sexual fulfillment (or is it meaningless sexual entanglements?) and Peter’s past as a frat-boy rapist. Director Mary B. Robinson orchestrates this drawing room duet with such a glacial pace, the actors’ adopting the WASP cliche of melodically condescending voices, that it almost put me to sleep. There’s nothing to care about here. By the time we get to the big reveal of Peter’s bad-boy college days, pulling us into Albee’s theme of humanity being just one step away from brutal animal nature, it just registers as distasteful.

When Peter leaves for the park, however, everything comes alive. Inside the humans are caged, their civilized exteriors just hiding their animal rage inside. Once outside, the domestication fetters are cast off. Albee may have felt the need to explain the backstory of The Zoo Story by showing us the interior of the cage with Homelife, but for me it was completely unnecessary. As Peter, Allin projects all of that just as he sits on the park bench, perfectly controlled as he reads his book, yet seething with an inner life. He just needs a few hours of escape, like all of us, and like all of us urban dwellers, he isn’t likely to get it. Along comes Jerry (James McMenamin), a tortured dreamer down a few socio-economic rungs from Peter, and he isn’t letting him go until the animal rage is released. In the amazing and rightly famous dialogue that follows, Jerry weaves a spell both funny and sad, as he tells the older man of his battle to win the loyalty of a mangey dog. It’s heartbreakingly real, performed with great sensitivity by McMenamin who really nails the essence of loneliness. All the while Allin listens and reacts with simplicity, making the inevitable conclusion to their duel all the more shocking.

That conclusion is still shocking even after forty-five years. It’s far more powerful than the clumsy, horrible reveal of rape in the first act. Why? It’s a playwright’s prerogative to rework his own words, but again, I wish he’d left it alone, because the brilliant power of his The Zoo Story is so intense it only highlights the flaws of Homelife. But that power is so seductive in this production, it still should be seen.

At Home at the Zoo is at Arena Stage through April 24. Located at 1101 Sixth Street SW, Washington, DC 20024. Closest Metro stop: Waterfront (Green line). For more information call (202) 554-9066.