"The Prodigal Son" is a trilogy of dramas, ambitious as Sophocles', each of its own the first since Milton's "Samson" to attempt the scale and evocative power of ancient myth. "The Prodigal Son," the first, restates the Biblical parable in starkly contemporary fashion-the prodigal, having dissipated seven years, now diseased and the lone attendant in a house of prostitution, attempts passage into his father's heart through a substitute, Komos, who possesses the youth and beauty he has squandered. "Esther," the second, enacts the Old Testament story with a geriatric Ahasuerus, King of Persia, and an Esther, Queen, heavy with child by Haman, the very soul who has condemned her race to death. "Gethsemane," the third, captures the agony in the Garden, an all too cynical eleven disciples, and a Judas, the Twelfth, whose betrayal of his Master is couched in peculiar regret. The Guard in Command-"These friends of yours are hardly bold./Strange as it might be/I'd trade your Judas for the pack of them./Woman that he was/he had the strength to betray you."