Send in the Search Team

Story where a crew is assembled to find out what happened to a previous set of adventurers, a colony, a lost ship, etc. Occasionally, the original people have "gone native" in any number of ways. For whatever reason, the rescue does not go smoothly, and the rescuers find themselves struggling to save their own lives.

See also Ghost Ship, which is somewhat similar. In video games, this is a way of showing up Late to The Party. Shares a few elements with Ontological Mystery.

Note: This trope was previously named "Heart of Darkness", which is the title of a work and has its own article. Heart of Darkness is an example of a Doomed River Expedition.

Anime & Manga

 * Patlabor parodies this twice.
 * The first incident happens when lunch ordered from the only restaurant in the area never arrives and the delivery boy vanishes along with the lunch. A second order is made, and this time Division 2 sends out Ota and Shinshi in a carrier truck to retrieve the lunch themselves. They never return, and the rest of Division 2 goes to investigate. Once they don't return either, the mechanics send a group to find out what happened. True to the trope, everything goes horribly wrong.
 * The second incident occurs, when the mechanics chase a food thief to a mysterious well near the Section 2 hangars. Once again, Divison 2 sends Ota and Shinshi first and quickly lose contact with them. And yes, once again, a second team is sent after them and everything goes horribly wrong.

Comic Books

 * This is the basic plot of several Tintin stories, particularly Recap, in which Tintin forms a search team to find his friend Chang in the Himalayas, although he's not even sure Chang is alive. Chang turns out to have been cared for by the Yeti. In some other stories, Professor Calculus has the habit of being kidnapped, so Tintin and Captain Haddock, possibly accompanied by others, have to set off to find him.

Film

 * The Alien series
 * Alien. The crew of the Nostromo must investigate an alien Distress Signal.
 * Alien S. The Marines are dispatched to LV-426 to determine why contact was lost
 * Apocalypse Now is loosely based on Heart of Darkness. It differs from most of the examples here in that the protagonist is sent on an assassination mission rather than to find out what happened.
 * And it was revealed later in the film that he was the second person they sent after the first one stopped reporting in.
 * Cannibal Holocaust.
 * Event Horizon.
 * Sunshine, sort of. The crew of Icarus II passes Icarus I in space, and initially decides not to stop. However,
 * Sunshine is really only a partial example, though, since, this trope still is quite the driving force behind the plot.
 * Miranda of Serenity, though in this case the protagonists are there for a slightly different reason and only found out that a search team had been sent after they arrive, by which time all that's left is a wrecked ship and an Apocalyptic Log.
 * Forbidden Planet.
 * The first Resident Evil film featured a team of commandos searching an underground laboratory to find out why the AI in control of the facility killed everyone.
 * The first Predator movie, though those participating don't actually know it. Their mission -- supposedly to rescue a cabinet minister shot down by guerillas -- is actually to find a special forces team that had been sent in to stop a guerilla offensive.

Literature

 * A few of Ray Bradbury's The Martian Chronicles follow plots of this type.
 * This is the plot of The Voyage of the Dawn Treader, part of The Chronicles of Narnia by C.S. Lewis.
 * In Michael Crichton's Congo, the protagonists are sent on a follow-up expedition to Africa after the original team was mysteriously killed by apes in the heart of the Congo.
 * Kim Newman's Alternate History novella Teddy Bear's Picnic, which essentially a reteeling of Apocalypse Now with British characters and a few nasty surprises.
 * In Dave Duncan's Seventh Sword trilogy, Wally Smith must find out what happened with his predecessor (Sonshu) so he doesn't repeat the same mistakes Sonshu made. Although his assingment isn't specifically to find out what happened, it's central to the plot.
 * Heart of Darkness, by Joseph Conrad.
 * Subverted hard in the short story Glacial by Alastair Reynolds. Everyone on the colony experienced severe dementia and died after researching alien slugs. The protagonists investigate...

Live Action TV

 * Star Trek
 * Star Trek the Original Series. This was the plot of multiple episodes, including "The Omega Glory", "The Tholian Web", "The Immunity Syndrome", "This Side of Paradise" and "The Doomsday Machine".
 * ''Star Trek the Animated Series': "The Lorelei Signal", "The Time Trap", "The Eye of the Beholder"
 * Star Trek the Next Generation: "The Arsenal of Freedom"
 * Star Trek Enterprise, "Terra Nova". A Vulcan ship is sent into the Expanse to find the Seleya, and ends up suffering the same fate before the NX-01 Enterprise stumbles across them.
 * Stargate SG-1, "The First Commandment".
 * In the Outer Limits TOS episode "The Invisible Enemy", astronauts are sent to Mars to learn why the members of the previous expedition vanished.

Video Games
"Boss: I hope this flight recorder data gives us a clue as to how these stupid lizards took over a Republic Assault Ship!"
 * In the video game Dead Space, you're a mechanic sent out after receiving a distress call from a mining vessel. When you arrive, you discover a Ghost Ship...only the "Ghost" is actually a "Space Zombie Virus"
 * What actually happened to the people on the ship is detailed in Apocalyptic Logs both in-game and an Expansion Pack Past comic and animated movie released alongside it.
 * System Shock 2 does this, sort of. The story begins as the maiden voyage of the newly-minted FTL-drive Von Braun, but when they get to Tau Ceti, it turns out that
 * Also, your character comes out of stasis to find
 * In Mass Effect 2, Jacob's loyalty mission has you tracking down his long lost father to a planet where he crash landed a decade ago.
 * A number of sidequests in both games also fit the trope. One example: a quest in the first Mass Effect has you looking for a science team that has gone missing. Turns out
 * The Baldurs Gate series has some quests along these lines. There's at least the deadly circus tent of illusions in Shadows of Amn. When you arrive, all people know is that since the last performance started, no-one who has gone inside has come out.
 * In Knights of the Old Republic, you're sent to find out what happened to the research facility in the Hrakert Rift on Manaan. They were all.
 * Republic Commando has Delta Squad do exactly this for their former ship, the Prosecutor, which has actually been taken over by Trandoshan slavers. The rest of your squad is captured; you have to free them and fight through the burnt-out remains of the ship.


 * Conquest Frontier Wars: In the intro, a ship was lost shortly after going through a wormhole. After that, a small search team sent through the wormhole was also lost. They then decide to send in the protagonist commander.
 * Phantasy Star IV has this as Hahn's primary motivation for joining the party-- he wants to join Alys and Chaz, professional monster hunters, and bring them with him to search for the missing Professor Holt. Unlike most other examples, though, several search parties have already been sent and come back with nothing; Alys and Chaz are recruited because it's assumed (by everyone but Hahn) that the Professor and his crew were killed by dangerous monsters.
 * One part of FEAR has you searching for a missing SFOD-D team. In the end, you only find their skeletonized remains.
 * Odium. You're a search team out to find the previous search team which was out to find out why were all communications with the city cut. (You'd think they'd give your team some heavier firepower after the previous guys failed...)
 * The third Avernum game has your party assigned to take over the mission of the first surface exploration team. While your primary goal is to deal with problems on the surface, you're also asked to figure out what happened to the earlier team if you can.
 * Dragon Quest IV: Ragnar's chapter starts with the king sending all his soldiers to investigate why children are disappearing from a nearby village..

Real Life

 * Sir Henry Morton Stanley's search for the Africa explorer David Livingstone (the famous words "Dr Livingstone I presume...?" are also often referenced).
 * In 1945, a group of 5 US Navy torpedo bombers disappeared in the Bermuda Triangle while on a routine training mission. Several planes and boats were sent out to look for them, and one of the rescue planes disappeared as well (generally assumed to have exploded in midair).