Doctor Who: Chaos Time

Doctor Who: Chaos Time is a video game. It features a heavy time travel element, allowing the player to jump between different times at the same location or different places at the same time.

Gameplay
The player directly controls the on-screen character through a third-person perspective to interact with people, objects, and enemies throughout the game. The player can also turn the camera around the characters, providing a 360° view. The player navigates the world on foot or by TARDIS. The game world is divided into multiple regions and time periods; the player can visit a region in multiple time periods and multiple regions at the same time period. For example, one region can be reached in the years 2309 and 2509, while the another can be visited in the year 2409. Some regions, because of plot points within the game, have alternate versions of themselves; for example, two versions of one region in the same year can be accessed once the plot has made the second version available. Connecting these regions is the TARDIS, which the player uses to travel between regions. The game's regions are represented as a branching path instead of being accessed linearly. New regions can be unlocked via plot points or by acquiring optional special items and the player may transfer between unlocked regions at any point by using the TARDIS.

When accessing a previously visited region, the player appears in the location of their last visit. Upon acquiring items called seals, the player can revert regions to their previous statuses to play through them again; regions can be unsealed again at any time. The game is automatically saved when players enter the TARDIS, as well as at key moments in the plot. The player may also manually save at any time. An in-game data log provides a bestiary and incidental information about the world of Doctor Who. When talking to characters, the game sometimes begins the Live Trigger system, in which the player chooses their response from several options; these dialogue options are generally not repeatable. The game also occasionally features temporal rifts, in which the player must complete a puzzle to close the rift and continue the game.

Setting
While the game starts off in the year 2011, the story jumps around several different time periods, and even parallel versions of different places, accessed via the TARDIS. While most of the game takes place on Earth, there are two other major locations. One is the Void Beyond, a limbo between time periods. The other location is the planet Valhalla. This place is a realm at the end of time where the a being keeps a dark energy called Chaos from escaping and destroying the timeline.

Characters
The two main playable characters are the Doctor and Amy Pond. Other characters are UNIT, and Rory Williams, Amy's fiancé. A new characters introduced are Hope and Alyssa from UNIT.

Plot
The game opens in 2011, Amy Pond believes she has a fiancé, Rory Williams, who nobody else remembers. Ss her hometown, Leadworth, is attacked by Cybermen. The Doctor appears to help and reveals to Amy she and Rory were his companions for two years but something has created a paradox causing her adventures with him to be erased and has erased Rory entirely. As a result, the Cybermen in Closing Time were never defeated and have begun to invade Earth. Amy agrees to join the Doctor in a journey to resolve these paradoxes by removing items and monsters, which are out of their original time and correct the timeline in hopes of finding Rory.

While journeying to 2013 to resolve a paradox, they meet and help Alyssa, a member of UNIT.

Traveling to 2018, they find Hope, who has become the leader of UNIT, with Alyssa as his assistant. They also find a recording of prophecies made by one of the seeresses of Paddra, who are believed to have died out centuries prior: one fragmented prophecy shows Rory on a planet called Valhalla. Paddra is shrouded by an eclipse, which the Doctor says is not supposed to happen for several centuries. While Amy and the Doctor resolve the paradox causing the eclipse, they encounter an alternate River Song, who has no memory of the Doctor or Amy and opposes their mission. After resolving the paradox, an alternative timeline appears in which there was never an eclipse. The repaired prophecy shows River in Valhalla opposing Rory. The Doctor claims that this takes place around 2408, devastating the human population as well as the world. Amy and the Doctorl move on, while Hope and Alyssa work on finding a way to prevent this future from happening.