Ekaśhloki Rāmāyaṇam
The story of Rāmāyaṇam in one shloka

ādau rāma tapo-vanādi gamanaṃ
ādau — at the beginning, rāmaḥ — (Lord) Rama, tapo-vana-ādi — to the forests of tapas or penance (Citrakūṭa, Daṇḍakāraṇya, and Pañcavaṭī), gamanam — went
At the beginning, Rāma (with wife Sītā and brother Lakṣhmaṇa) went to the Tapovanās, forests of tapah or penance, during his 14 year vanavāsa.

hatvā-mṛgaṃ-kāñchanaṃ
hatvā – killed, kāñchanam - golden, mṛgaṃ – deer
He killed the asura Māricha, uncle of Rāvana, who came in the disguise of a golden deer.

vaidehī-haraṇaṃ
vaidehī haraṇaṃ – Vaidehi was kidnapped
The evil asura Rāvana, who came in the disguise of a sadhu asking for alms, kidnapped Sītā.

jaṭāyu-maraṇaṃ
jaṭāyu maraṇaṃ – Jatayu was killed
The great, large gṛudhra bird Jaṭāyu, fought with Rāvana to try to stop him. Rāvana cut his wings off but Jaṭāyu held on to his life until he could tell Rāma and Lakṣhmaṇa of Sita's kidnapping before he died.

sugrīva-sambhāṣaṇaṃ
sugrīva-sambhāṣaṇaṃ - discussions with Sugrīva
Hanuman met Rāma and Lakshmana at the banks of Pampa river and introduced them to Sugrīva. They shared their stories and became friends, pledging to help each other.

vālī-nigrahaṇaṃ
vālī-nigrahaṇaṃ - Vālī was subdued
Vālī committed adharma or an immoral act by taking away his own brother Sugrīva's family and kingdom forcefully. Since Rāma would never let adharma win, he subdued Vālī and returned Sugrīva's family and kingdom to him.

samudra-taraṇaṃ
Samudra - Sea/Ocean, taraṇaṃ - was crossed
Jaṭāyu's brother Sampāti tells the vānaras that Rāvaṇa carried Sītā across the ocean to Laṅkā. Hanumān has forgotten his own inner strength and hesitates to go across the ocean. The wise old bear Jāmbavanta restores his confidence by reminding him of his true power and empowered, Hanumān undertakes the leap to Laṅkā.

laṅkā-purī-dāhanaṃ
laṅkā-purī-dāhanaṃ - the city of Lanka was burnt
Hanumān searches through Laṅkā and finds Sītā, reassuring her of Rāma's coming rescue. He kills many asuras, allows himself to be taken before Rāvaṇa and delivers Rāma's message and warning. His tail is set on fire and he escapes, using the flames to burn Laṅkā, and returns to report back to Rāma.

paścād-rāvaṇa-kumbhakarṇa-hananaṃ
paścāt – after that; rāvaṇa-kumbhakarṇa-hananaṃ - Rāvana and Kumbhakarṇa were slayed
During the great war between Rāvana's huge asura army in their own land Laṅkā and Rāma's smaller but brave vānara army that built a bridge to cross the ocean and fight the war in a strange land, dharma won over adharma and Rāma defeated both powerful asuras Rāvana and Kumbhakarṇa.

yetaddhi-rāmāyaṇam
etat + hi - like this is; Rāmāyaṇam
Like this is the great story of Rāmāyaṇam.