Although Kalidasa made some negligible changes to the plot, the play expands upon an episode mentioned in the Mahabharata. The protagonist of Abhijnanasakuntalam is Shakuntala, daughter of sage Vishwamitra and the apsara Menaka.
A long while ago, the mighty sage Vishwamitra was engaged in strenuous meditation. Fearing that he may acquire more prowess than the Gods, Lord Indra decided to send down one of the most graceful heavenly damsel Menaka to earth, to interrupt his meditation. She succeeded to lure him away and they had a beautiful daughter. However, Menaka had to return to heaven, so they left the child amidst a picturesque garden near a lake. In the meantime, a swan in the lake saw the crying child and gave it some water. Just then a sage named Kanava, who was passing by, witnessed the swan lending water to the child. He decided to take the child home and named it "Shakuntala", meaning - one fed by a swan.
Shakuntala grew up to be a fine-looking young lady just like her mother Menaka. One day, King Dushyanta came by Shakuntala in the forest and immediately fell head over heels for her. He asked her to marry him and thus stayed behind with her in the ashram. After some days, the King received news of agitation in the capital city and he was summoned immediately to return soon to deal with the situation. He left reluctantly, but promised to return soon and take his beloved with him. As a token of love, he gave her a ring and promised to return back soon.
One day, when Shakuntala was reclining right outside the house, sage Durvasa, legendary for his wrath, paid a visit to the ashram. Lost in her thoughts, Shakuntala failed to acknowledge his revered presence. Durvasa was terribly exasperated and cursed Shakuntala stating that the one whom she was recalling about, would forget her face. Shakuntala pleaded for mercy and explained her pitiable situation. The sage however softened a bit and spoke that if the king chanced upon the ring he gave her, he would remember everything. Shakuntala took immediate preparations to travel to the kingdom, as there was barely any news from the king.
She had stopped by a lake to drink water and regrettably the ring gifted by king Dushyanta slipped out of her finger and a fish swallowed it. She thus reached the royal palace, but Dushyanta failed to distinguish her. She then remembered the ring and when she lifted her hand to show him the ring, she realised at last that she had lost it somewhere. Crestfallen, she returned back to the forest without any companions. After sometime, a fisherman in the royal palace encountered the ring in the stomach of a fish he had caught. He immediately acknowledged the ring and rushed to the king to show it to him. Dushyanta recalled everything and hurried to apologise to Shakuntala. However, it was too late a situation that could be revived. The freshly prudent Dushyanta had defeated an army of Titans and was honoured by Indra with a journey through the Hindu heaven. Returned to earth years later, Dushyanta found Shakuntala and their son unexpectedly and discerned them instantly. She forgave him and the three lived together happily.