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Fighting so many at once is a dangerous prospect, unless you are a truly mighty warrior. This many so close together suggests a nest nearby - if we find it and destroy it, we might have better luck.Waking Cloud

River Monsters is a main quest in the Fallout: New Vegas add-on Honest Hearts.

Quick walkthrough

Honest Hearts main quest: River Monsters
Deal with the yao guai at Pine Creek then head up the road.
Kill the yao guai that block the road in order to get through.
Destroy the yao guai cave by planting mining explosives inside.
Reward: Variable XP
Leads to: Gathering Storms

Detailed walkthrough

From Pine Creek, the Courier can either enter the nearby cave to set explosives and close off the entrance, or kill the yao guai outside the cave. The cave option does not require combat. Completion of either option ends the quest successfully, and the particular method chosen has no effect on the rest of the game.

If opting to collapse the cave entrance, the cave must be entered. From here, the cave may be explored, and three marked positions on the floor (that look like transparent "mining explosives") mark where the explosives must be placed. The "mining explosives" are not traditional "items" that can be carried; instead, they are a part of the cave and only need to be enabled. They are visually identical to C-4 plastic explosive. There are three yao guai in a central area of the cave, but killing them is not a requirement for this quest as they can be avoided while placing the explosives. When all three explosives are set, the Courier should exit the cave and trigger the mining detonator, sealing the cave and completing the quest.

If the Courier chooses to kill the yao guai outside the cave, they can simply follow the map markers to the targets and dispatch them. Once all of the target yao guai are killed, the quest is complete.

Quest stages

10 Deal with the Yao Guai at Pine Creek.
35Quest finishedOptional: Collapse the Yao Guai Cave
36 Plant mining explosives at key points within the cave.
37Quest finishedLeave the cave and set off the charges with the mining detonator.
38Quest finishedOptional: Kill the Yao Guai at Pine Creek.


  • Even if the Courier kills the yao guai in the cave before this quest, they may respawn. If they did not, the only way to complete the quest is to plant the explosives.
  • Look closely for the charge markers, as they blend in with the cave floor making them difficult to see in the dark.
  • Waking Cloud will comment that it is very dangerous to directly attack the yao guai at Pine Creek. She can be reassured, but will remain skeptical.
  • Once the explosives are set off, the yao guai cave cannot be entered again.
  • It is possible to complete both optional parts of the quest, but it requires good timing. After killing the third and final yao guai, it is possible to quickly switch to the detonator and collapse the cave (assuming the mines were activated previously). However, this will not give any extra rewards.
  • This quest is similar to Stop the Radscorpions from Fallout.


PCPC If the explosives are planted in the cave without triggering them, and then the yao guai are killed at Pine Creek, the quest will be compromised and cannot be completed.[verified]

Main quests
Act 1Ain't That a Kick in the Head · Back in the Saddle · By a Campfire on the Trail · They Went That-a-Way · Ring-a-Ding-Ding!
Act 2Wild Card (Wild Card: Ace in the Hole, Change in Management, You and What Army?, Side Bets, Finishing Touches) · The House Always Wins (I, II, III, IV, V, VI, VII, VIII) · Render Unto Caesar · Et Tumor, Brute? · Things That Go Boom · Kings' Gambit · For the Republic, Part 2 · You'll Know It When It Happens/Arizona Killer
Act 3No Gods, No Masters · All or Nothing · Veni, Vidi, Vici · Eureka!
Side quests
New California RepublicAnywhere I Wander · Back in Your Own Backyard · Bitter Springs Infirmary Blues · Boulder City Showdown · Can You Find it in Your Heart? · Climb Ev'ry Mountain · Don't Tread on the Bear! · Emergency Radio · Eye for an Eye · Flags of Our Foul-Ups · Hard Luck Blues · I Don't Hurt Anymore · I Put a Spell on You · Keep Your Eyes on the Prize · Medical Mystery · No, Not Much · Pressing Matters · Restoring Hope · Return to Sender · That Lucky Old Sun · The White Wash · There Stands the Grass · Three-Card Bounty · We Will All Go Together · You Can Depend on Me
Caesar's LegionBeware the Wrath of Caesar! · Caesar's Favor · Caesar's Foe · Caesar's Hire · Cold, Cold Heart · I Hear You Knocking · The Finger of Suspicion · We Are Legion
The StripBeyond the Beef · Bye Bye Love · Classic Inspiration · How Little We Know · Pheeble Will · Talent Pool · The House Has Gone Bust! · The Moon Comes Over the Tower
Freeside & Outer VegasBirds of a Feather · Bleed Me Dry · Debt Collector · G.I. Blues · High Times · Someone to Watch Over Me · The Coyotes · Wang Dang Atomic Tango
BoomersAnt Misbehavin' · Sunshine Boogie · Volare! · Young Hearts
Great KhansAba Daba Honeymoon · Cry Me a River · Don't Make a Beggar of Me · Oh My Papa
Powder GangBooted · I Fought the Law · Run Goodsprings Run · Why Can't We Be Friends?
Brotherhood of SteelEyesight to the Blind · Still in the Dark · Tend to Your Business
OtherCome Fly With Me · Crazy, Crazy, Crazy · Ghost Town Gunfight · Guess Who I Saw Today · Left My Heart · My Kind of Town · The Legend of the Star and A Valuable Lesson · Unfriendly Persuasion · Wheel of Fortune
Companion questsED-E My Love · For Auld Lang Syne · Heartache by the Number · I Could Make You Care · I Forgot to Remember to Forget · Nothin' But a Hound Dog · One for My Baby
Unmarked questsA Bit of Slap and Tickle · A Final Plan for Esteban · Access Powers · All Fired Up! · An Ear to the Ground · Andy and Charlie · Arachnophobia · Arizona Scavenger · Barton the Fink · Bear Necessities · Big Winner (Atomic Wrangler, The Gomorrah, The Tops, Ultra-Luxe, Vikki & Vance) · Bounty Killer (I, II) · Brotherhood Bond (I, II) · Caching in at the Cove · Cajoling a Cudgel · Claws Mended · Claws Out · Dealing with Contreras · Defacing the Humble Stone · Democracy Inaction · Don't Poke at the Bear! · Eddie's Emissary · Exhumin' Nature · Fight Night · Flogging a Dead Corpse · Friend of the Followers · Gland for Some Home Cooking · Harder, Better, Faster, Stronger · Hat's Entertainment · Help for Halford · Hidden Valley computer virus · Highway to the Danger Zone (I, II) · Honorary Rocketeer · I Love Bananas · Iron and Stealing · Keith's Caravan Charade · Laurifer Gladiator · Lenk's Bad Debts · Lily and Leo · Long-Term Care · Malleable Mini Boomer Minds · Maud's Muggers · Meeting an Equal · Missing a Few Missiles · Most Wanted · Not Worth a Hill of Corn and Beans · Old School Ghoul · A Pair of Dead Desperados (I, II) · Papers, Please · Pistol Packing · Playing on the Old Joana · Poor Meat Never Makes Good Soup · Powder to the People · Power to the People · Razzle Dazzle! · Reach for the Sky, Mister! · Rest and Resupply · Ringo's Caravan Rules · Rotface's Loose Lips · Saving (or Savaging) Sergeant Teddy · The Screams of Brahmin · Silus Treatment · Short-Term Treatment · Smooth-Talking Criminal · The Star Showdown · Strategic Nuclear Moose · Straus Calls · Strip Search · Suits You, Sarah · Tags of Our Fallen · A Team of Moronic Mercenaries · Thought for the Day · Tourist Traipse · Trudy's Radio Repair · A Trusted Aide · Useless Baubles or Fancy Trinkets? · We Must Stop Beating Like This · We Must Stop Meeting Like This · Wind-Brahmin Wrangler · You Gotta Break Out a Few Eggs · You Make Me Feel Like a Woman
Add-on quests
Dead MoneySierra Madre Grand Opening! · Find Collars (8: "Dog", 12: Christine, 14: Dean Domino) · Fires in the Sky · Strike Up the Band · Mixed Signals · Trigger the Gala Event · Put the Beast Down · Last Luxuries · Curtain Call at the Tampico · Heist of the Centuries · Big Winner, Sierra Madre
Honest HeartsA Family Affair · Arrival at Zion · Bighorners of the Eastern Virgin · Chaos in Zion · Civilized Man's Burden · Crush the White Legs · Deliverer of Sorrows  · Departing Paradise · Flight from Zion · Gathering Storms · Gone Fishin' · Happy Trails Expedition · Prisoners of War · Retake the Bridge · River Monsters · Rite of Passage · Roadside Attraction · Sanctity of the Dead · The Advance Scouts  · The Treacherous Road · The Grand Staircase · Tourist Trap
Old World BluesAll My Friends Have Off Switches · A Brain's Best Friend · Coming Out of Her Shell · Field Research · He Came... And Went · Influencing People · Midnight Science Fiction Feature! · Old World Blues · On the Same Wavelength · Picking Your Brains · Project X-13 · Sonic Emitter Upgrade · Welcome to the Big Empty · What's in a Name? · When Visitors Attack! · X-2: Strange Transmissions! · X-8 Data Retrieval Test · X-8: High School Horror! · X-13: Attack of the Infiltrator!
Lonesome RoadThe Reunion · The Silo · The Job · The Launch · The Tunnelers · The Divide · The Courier · The End · The Apocalypse