Shortly after the completion of Happy Trails Expedition and the Courier's initial arrival in Zion, a group of White Legs will attack the caravan, killing everyone but the Courier. There is no way to save the caravan members, as their deaths are scripted, and many of the ambushers can't be damaged or killed until the other caravan members are all dead. The player may opt instead to attack the caravan itself after arriving (for a loss of Karma), earning the experience from killing them (though this immediately triggers the attack by the White Legs on both the caravan and the Courier).
After crossing the bridge towards the rest of Zion, there will be another attack on the player by a White Legs tribal from a distance, standing upon a large rock. This ambush will, in turn, become thwarted by Follows-Chalk, a scout from the Dead Horses tribe who can join the Courier as a companion. The player can opt to let Follows-Chalk join immediately, or send him away. If Follows-Chalk joins the Courier, he will provide a scripted commentary on the way to Dead Horses camp.
If the player allows Follows-Chalk to join, he will point out a hollow log that contains random minor loot. Not far down the path towards Dead Horses camp, a non-hostile giant yao guai will make a brief appearance in a scripted event. Further along the path, Follows-Chalk will note a cliff (the name of the cliff with a view), which is the first opportunity to make use of the Well-Stacked Cairns perk. When getting close to the Dead Horses camp, Follows-Chalk will warn the player about traps set in the river to keep marauding White Legs at bay. Furthermore, if the player wanders too far off course, he will comment and remind the player they're supposed to be heading towards his camp.
On arrival to the Dead Horses camp, the Courier is told to enter Angel Cave and follow it up until they find their leader, Joshua Graham. Engaging in conversation with Graham will complete the quest.
The player can also opt to simply kill Follows-Chalk, which fails this quest and triggers Chaos in Zion. Triggering Chaos in Zion disallows participation in all other quests in the Honest Hearts add-on, and subsequently all of its quest-related trophies, so if the player wishes to experience any other additional quests, care should be taken not to accidentally kill Follows-Chalk when crossing the bridge and dealing with the last ambushing White Legs member.
Follows-Chalk will kill the White Leg tribal lying in ambush across the bridge. Attempting to shoot the ambusher can lead to to accidentally shooting Follows-Chalk instead, turning the Dead Horses tribe hostile.
While talking to the Dead Horse Disciple of Canaan upon entering Angel Cave, an Intelligence stat check of 7 allows the player to demonstrate an understanding of the tribal dialect. The Sneering Imperialist perk works as well in this regard.
The duffle bags located near the ambush site are safe to store items in until the add-on is completed.
xbox360 If you interrupt the dialogue during the opening of this quest by going to the load menu, the dialogue can lock up before Stella can say her final lines to Jed—leaving you unable to move with the other caravan members just standing around, saying nothing. [verified]
xbox360 One of the White Legs might become invincible if you leave the ambush without defeating them, thus making it impossible to complete the optional part of this quest. [verified]
xbox360 During the ambush, the White Legs may become invisible until the combat is over. [verified]
ps3 Some White Legs may be non-hostile and too far away from the cliff to kill them, making the optional part of the quest impossible to complete. [verified]
xbox360 Jed Mastersons' body will not disappear after his death during the White Legs assault. [verified]
ps3xbox360pc Follows-Chalk may briefly appear as an enemy when attacking the White Legs. This can lead to the player accidentally killing him thus breaking the main quest. [verified]