Blood Ties

Blood Ties is a side quest in Fallout 3 as well as an achievement/trophy.

Synopsis
A recent addition to Megaton, Lucy West, is looking to get into touch with her family in Arefu. Tasking the Lone Wanderer to carry an envelope to her family. The family however is either dead or missing, and a mysterious and gruesome scene within their home. A search for Lucy's brother will only end in tears, a conflict between the Arefu citizens, and local blood-drinking gangers will come to a final conclusion.

Walkthrough - Finding Lucy's family

 * 1) Speaking to Lucy West in Megaton, she will ask for the Lone Wanderer to deliver a letter to her family in Arefu. Should the quest be accepted, Lucy will hand over an envelope, and will mark the location of Arefu on the Pip-Boy 3000.
 * 2) Upon reaching Arefu, a man by the name of Evan King will toss a scripted grenade as the Lone Wanderer approaches the town. He will then apologize and explain that the town has been under constant attack by The Family, a local gang. Evan will ask for the Lone Wanderer to help check in on the Ewer, Schenzy, and West residences, to make sure that everyone is all right (this starts the quest should it not have been started through Lucy).
 * 3) When checking in on the residents, it will be discovered that while the Ewer and Schenzy families are safe, the bodies of Lucy's parents will be found; further examination shows that the bodies have bite marks on their necks (requires a Medicine skill of 30 or higher), that there is no significant blood loss present (50+ medicine skill or higher required), that the teeth marks are from human teeth (75+ or higher in medicine skill), and that there is train yard residue on the bodies (90+ medicine skill or higher required).
 * 4) Reporting back to Evan King, he will ask about the fate of Lucy's brother, Ian. Upon discovery that he is missing, Evan will mention having seen Ian with Vance, the leader of The Family, after their last raid on the town. Evan will also mention that The Family might be hiding out inside of either the northwest Seneca station, Hamilton's hideaway, or at the Moonbeam outdoor cinema. None of these are correct; should the Lone Wanderer have noticed the train yard residue, it will be possible to ask Evan if there are any train yards in the area. This will allow Evan to add a marker for the correct location, the Meresti trainyard.

Conclusion
Before continuing onward, should the Scoundrel perk have been taken, Lucy can be returned to, and an incentive of caps can be demanded of before agreeing to go look for her brother. In return, Lucy will hand over 100 caps, with no Karma penalty.

Walkthrough - Finding Ian

 * 1) The Family resides within the Meresti station, which can be reached via the tunnels underneath the Meresti trainyard, or much more inconveniently, through the tunnels found underneath the radioactive barrels in the back of Murphy's place within the northwest Seneca station. Beware of various traps, including bear traps, frag mines, a rigged baby carriage, and an assortment of tripwire traps that set off rigged shotguns, grenade bouquets, and even a batting machine.
 * 2) The front gate to the Family's hideout is guarded by Robert, who will allow outsiders into the Family's home for a 100 caps bribe, or for free should the Lone Wanderer have Lucy's letter on their person. Peaceful entrance can also be instigated by passing a Speech check with Robert, or by using a speech option from the Cannibal perk. Alternatively, Robert can be killed, or the terminal adjacent to his post can be hacked into in order to unlock the station door, although these alternatives will turn The Family entirely hostile.
 * 3) The next task is to locate Ian West, and to determine if he is even still alive. Several members of The Family will reveal Ian's location, and the password to unlock the room where he is meditating. These are the possible scenarios:
 * 4) The leader of The Family is Vance, a mysterious and charismatic man who is trying to help the members of his "Family" overcome their hunger for human flesh, by drinking human blood akin to the mystical vampires in the stories from before the Great War. If the Lone Wanderer fails a Speech check, Vance will advise for them to learn the rules of The Family by asking other members and reading from the terminal in the main lobby. Should the Lone Wanderer pass the Speech check, uses the Cannibal perk, or reads the rules and explains that they understand The Family, Vance will give the pass code that allows entry into Ian's meditation room.
 * 5) Alan notices that Justin has been trying to befriend Ian, and suggests that the Lone Wanderer talk to Justin about him. Justin believes that Ian belongs with The Family, having witnessed the murder of his parents and done nothing. If the Lone Wanderer suggests that Ian needs an 'outside voice' to help, and passes the subsequent Speech check, Justin will reveal the pass code that allows entry into Ian's meditation room. The Impartial Mediation perk gives a similar dialogue option with an identical result.
 * 6) Karl will become annoyed if asked about Ian, although he can be seduced by using the Black Widow perk (if the player is female), or he can be convinced with a high Strength (both sexes). In either scenario, Karl gives up the pass code to Ian's meditation room.
 * 7) Brianna also feels that being with The Family is the best solution for Ian, but that he could use an outside friend. Should the Lone Wanderer have the Lady Killer perk (as a male), he will have the option to seduce Brianna into handing over the password for the room where Ian is. Having the Scoundrel perk or a high Charisma will work as well.
 * 8) Holly, Vance's wife, can be persuaded to reveal the pass code with the Scoundrel perk or a high enough Charisma stat.
 * 9) Vance can simply be killed, and the pass code looted from his remains. This will cause for the rest of The Family to become hostile, permanently attacking on sight. Each family member killed will result in negative Karma at this point. Ian will be angry that Vance has been killed, but will give the Lone Wanderer the same ultimate options regardless, so long as they do not respond flippantly to Vance's death. As an alternative, the Lone Wanderer may also goad Vance with certain conversation options, finally calling him a "psycho", in which he will order The Family to attack - this will allow for their deaths without the consequences of negative Karma from killing them (note: This path must be taken before Ian comes to any decision. See bugs).
 * 10) Speaking with Ian will confirm that he was not kidnapped, as he voluntarily joined The Family after killing his own parents. After a childhood encounter with a threatening wastelander, Ian has craved human flesh and blood, even that of his own mother and father. The Lone Wanderer is then faced with the choice of convincing Ian to leave, which requires either the letter from his sister Lucy, or by passing a Speech check if Vance is still alive, or leaving him with The Family.

Walkthrough - Settling the score

 * 1) Ian's decision must be relayed to Evan King back in Arefu, and depending on which choice Ian made, the appropriate parties will react with either enthusiasm or disappointment. Reporting the news of Ian's decision to King will result in a sizable amount of good Karma, regardless of Ian's ultimate choice. After Ian's decision, The Family and the residents of Arefu are considered to be the same faction even before a deal is between the two parties.
 * 2) At this point, a decision needs to be made, to determine the relationship between The Family and Arefu:
 * 3) Vance may be convinced to either not attack Arefu, or to help defend Arefu should he and The Family have not already been wiped out.
 * 4) If the Lone Wanderer simply asks Vance to stop attacking Arefu, Vance will agree.
 * 5) Through a successful Speech, Medicine, or Intelligence check, the Lone Wanderer can also convince Vance to enter into a deal involving donated blood packs instead of attacking the residents of Arefu for their blood.
 * 6) Regardless of the conversation choice, Vance will award the player with the Shishkebab schematics. Should the Lone Wanderer have suggested that The Family guard Arefu in exchange for blood packs, Alan will be dispatched to Arefu, fulfilling their end of the deal.

Behind the scenes

 * "Vespertilio", the password to Ian's cell, is a genus of Vespertilio Vespertilionidae bats.
 * Alan informs the Lone Wanderer about the "Meresti" name originating from that of a town in Romania, in which he is referring to the town of Mereşti.

Bugs

 * If the player kills any member of the after Ian makes his decision, the inhabitants of Arefu will turn hostile even though no one from the town was directly attacked or killed. This is due to the fact that Arefu and the Family become one faction after Ian makes his decision, rather than after the deal is struck between Evan and Vance.
 * Sometimes, after getting Ian West to return to Arefu, the residents of Arefu will turn hostile for no reason and the quest will fail.
 * Rarely, when you start the quest normally from Lucy in Megaton then talk to Vance, giving the letter to Ian when talking to him will not remove it from your inventory.
 * When you first approach Arefu, Evan King may run past you to attack an enemy if you led them there. If this happens, the explosion will still occur and you will be frozen in place as the game waits for the encounter to occur. You can either load a previous save from when not on the bridge and kill the enemy following you, or wait for Evan King to come back, which can take a while. Eventually, he will walk past you and return to his usual position, in which the dialogue sequence will then initiate. The game may freeze.