When Louise (Carrie Coon) finds out her mother may be dying, she lies and tells her that she’s marrying her boyfriend Jonathan (William Jackson Harper).  That is, she offers fake information in order to please.  As “I shall please” is the literal meaning of the word “placebo,” Louise has given her mother a placebo wedding.  “Placebo,” as we learn from Jonathan, who is a doctoral candidate in the classics, were also people: professional mourners who, in the Middle Ages, with so much death, were paid to “act like they care.”

This tension between the authentic and the performed, between cures and pleasures, is at the center of Melissa James Gibson’s short but satisfying new play, Placebo.  The title literally refers to Louise, who is also working on her doctorate and helping to test a new drug meant in increase female sexuality.  Her patient (Florencia Lozano), a volunteer in a double-blind trial, cannot know whether she is getting the control pills or the real thing.  Nevertheless, she finds herself affected by “the power of something or the power of nothing.”

As Jonathan completes his dissertation on Pliny the Elder—seven years in the making—his relationship with Louise deteriorates, and she gradually gets closer to a colleague, Tom (Alex Hurt).  Explaining the drug to him, she says, “Viagra’s purely about mechanics.  Penile mechanics.  Whereas this drug aims to get inside a woman’s mind,” to affect the communication between the mind and the vagina.  “What language do they speak?” Alex asks.  The answer, apparently, is “Vagenglish.”  Indeed, it seems like all four of these characters, failing to communicate in plain English, are struggling to recover an older language, whether it is Latin or simply sexual contact.

Wordplay is the main relief in an otherwise rough-going work, everyone here having fun with confusions about “kneading” and “needing” or “aural” and “oral.”  The cast is uniformly excellent, especially Mr. Harper, whose Jonathan is difficult to penetrate, and who exposes himself most when discussing an author who has been dead for nearly two millennia (thus the act of betrayal when he hides his dissertation from Louise but shows it to an ex-girlfriend).  Mr. Hurt, too, stands out, bringing out the tragic underpinnings of Alex’s misanthropy without relying on broad expressiveness; speaking almost exclusively in a hesitant monotone, he allows us only brief glimpses into his sadness.

“Do you think it becomes real?” Louise asks Jonathan of the mourning. “Does it make you feel sad after a while?  Or happiness—does fake happiness make you happy?”  In Ms. Gibson’s world, where conventional communication has more or less broken down, where lovers do not even tell each other what pleases them sexually, I certainly hope so.

Placebo runs through April 5th at Playwrights Horizons.  416 W. 42nd Street  New York, NY.  1 hour 35 minutes.  No intermission.