Short answers, pulled from the story.
The afterlife, or life after death, is the speculation that the essential part of an individual's stream of consciousness or identity continues to exist after the physical body dies. The surviving aspect varies between belief systems and may be a partial element or the entire soul carrying personal identity. Major views derive from religion, esotericism, and metaphysics.
Ancient Egyptians believed the dead faced a demanding ordeal in the Hall of Two Truths, where the heart was weighed against the Shu feather of truth taken from the goddess Ma'at. If the heart was lighter than the feather, the soul could pass on, but if heavier it was devoured by the demon Ammit. They also believed mummification and proper entombment in a mastaba were necessary to live again in the Fields of Yalu.
Reincarnation is the conjecture that an aspect of a living being begins a new life in a different physical body after each death, part of the Samsara and karma doctrine of cyclic existence. It is shared by Buddhism, Hinduism, Jainism, and Sikhism, and was held by Greek figures such as Pythagoras and Plato. The nature of the continued existence is determined by the actions of the individual in their ended life.
The Greeks believed Hermes carried the dead soul to the banks of the River Styx, where the ferryman Charon took it across to Hades if the family had placed coins under the deceased's tongue. The soul was then judged by Aeacus, Rhadamanthus, and King Minos and sent to Elysium, Tartarus, or the Asphodel Fields. Tartarus punished the consciously evil, while the Elysian Fields rewarded those who lived pure lives.
Islam teaches that on Judgement Day God raises all mankind and the jinn from the dead and evaluates their actions, recorded in two books of good and evil deeds. The resurrected cross the bridge of As-Sirat over hell, with the righteous reaching the gardens of Jannah and the condemned falling into Jahannam. After death, two angels named Munkar and Nakir first question the dead about their faith.
In 1901, the physician Duncan MacDougall weighed dying patients in an attempt to prove the soul was material and measurable. His results varied considerably, but the figure of 21 grams became synonymous with the supposed mass of a soul and gave the 2003 movie 21 Grams its title. His results have never been reproduced and are generally regarded as meaningless or of little scientific merit.
Purgatory in the Catholic Church is where those who die in God's grace but are still imperfectly purified undergo purification before entering Heaven. The Latin noun purgatorium, meaning place of cleansing, was used for the first time to describe this painful purification of the saved. Those who die in unrepented mortal sin instead go to hell.