The Sims 4 StrangerVille Mystery Aspiration

Story Ending: Vaccines & Source of the Infection The Mother Plant

The Mother Plant in StrangerVille is the Source of the Infection
The Mother Plant is nasty and requires a team of Vaccinated Sims to fight and finish the StrangerVille Story.

Having entered the Secret Lab's basement, we have now found the massive Mother Plant, the source of the infection. She's causing all this strangeness and we need to prepare for a confrontation by doing a little science. Bring your Infection Scanner, as you're going to need it.

Develop a Test Vaccine

Get more spore clusters for a vaccine in The Sims 4 StrangerVille
You'll spend a while getting the many Spore Clusters you need, but the state of the world makes it easier. Again, stick to the lab for gathering these.

In order to make a vaccine we can test, we are going to need 5 Spore Clusters and 1 Bizarre Fruit. Each, and we'll need at least 6 or 7 of them. I did 15 spores to start and 15 later. You should already be good at this if you read Part 3, but I'll repeat it for people who did it out in the world - scan for Spore Clusters in the Secret Lab, it's highly effective and you'll get 5 each time. After the first round of 15, work on getting the second component (the fruit) while the battery on the Infection Scanner recharges.

Stop the Infection and finish the story in THe Sims 4 StrangerVille
You'll finish the story if you can stop the infection. StrangerVille is in a bad state with many plants all over, so getting Bizarre Fruit you need for the Mother Plant Battle will not be very hard.

You will also need 3 of the Bizarre Fruit for now, which come from the odd plants all over town. When you walk up to one and click it, you get the Nurture option if it's ready. This will cause the plant to bloom and yield a Bizarre Fruit each time. You'll need to find 3 plants for this step, as they only yield 1 fruit.

Making Vaccines in The Sims 4 Strangerville to fight The Mother Plant
Vaccines are required in order to fight the Mother Plant

Take your 15 Spores and 3 Bizarre Fruit to the Chemical Analyzer in the Secret Lab and pick up some others after your scanner recharges. You'll want full energy to give you enough time to make 3 Test Vaccines. This is ultimately saving time vs making multiple trips, but you do it however you feel comfortable.

Testing the Vaccine

Testing the vaccine on an infected Sim

We can now make Test Vaccines at the Chemical Analyzer in the Secret Lab's Basement. Make a total of 3 and you can begin testing them. Head out to town and look for Sims who are obviously infected and under the Mother's influence. The Vaccine probably won't work at first, but you can learn a bit from it. When you have tested it on 3 Sims, you should finally have enough data.

Vaccinating a Sim to fight the Mother Plant and finih the Sims 4 StrangerVille Mystery
Use the actual, working vaccines on the friends you'd like to bring along to fight the Mother Plant.

Once you've tested the 3 vaccines, you should get a notification that it now works and you are able to produce a true cure to the StrangerVille 'virus'. While you can choose to leave the world this way and vaccinate Sims you like, you should probably move on. The game gives you options to set the Strangeness however you like, even with the story completed.

Recruiting Sims To Fight Mother

Now you need 3 vaccinated friends who you will also recruit to fight mother. Find a Sim, vaccinate them, then get them to join you. They need to be vaccinated to be able to go. If a Sim is a local, it is much easier to get them to join. If the Sim's from out of town you'll need to take them to StrangerVille and get them to at least 30% friendship before you can ask them to fight Mother. They'll tell you this world's problems are not their own.

Fighting The Mother Plant

Ask Sims to fight the mother plant in Sims 4
Vaccinate, then recruit to assemble your group of Sims to fight the Mother Plant in StrangerVille's Secret Lab

With 3 recruits you are now ready to fight Mother. Head to the lowest level of the lab, using Travel With that comes up when you use the map. The three Sims don't have to be nearby but they may join the fight a tad sooner if you use group move and make sure they are following you to the bottom. Otherwise they seem to attempt to teleport so they are in the right place. When you get to the last door and walk up to Mother, you'll get to choose 'Fight With' and pick all three of your allies.

MotherPlant Battle

Beating the Mother Plant boss in The Sims 4 StrangerVille Game Pack
The Motherplant battle is very unique and offers some unexpected fun. I enjoyed fighting her and many of you will, too. Be sure to read what is after the fight for some advice on dealing with her later as you are not exactly killing her but getting her to cut the crap.

The Mother Plant battle may be foreign to a lot of Sims players. This fight is kind of like an isometric RPG with real-time combat. Your Sims will deal damage to her while she deals infection to you. The player has an infection meter which must not reach full, while the Mother Plant has health that must be brought down to 0. Clicking allies, you can issue them commands and clicking the Mother Plant issues group commands or those for your own Sim. You have a lot of options for how you approach this fight. Will you have each of them fight one of the zombies that comes to attack, or stave them off with a Warbling Warcry (scares Zombies). Only the absolutely wrong decision will wreck your day (ie, doing something that increases damage but also infection when you are nearing full infection).

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Throwing an infection vaccine at the mother plant in The Sims 4
Allies can be ordered to 'Throw Infection Vaccine' which deals big damage to the Mother Plant (about 8% of her health).

Click the Mother Plant herself to get a menu that lets you choose Group Commands and use abilities with your own Sim. These change how much damage/infection you take or deal direct damage. Here's a list:

Sim Commands

  • Throw Infection Vaccine - Does the same as when an Ally throws one, as far as I can tell.
  • Retreat! - Your allies take more damage, but so too does the Mother Plant.
  • Mega Spray - Deals damage similar to throwing an Infection Vaccine, 90 min cooldown.

Group Commands

  • Be Careful - You and Allies take less infection but also deal less damage to the Mother Plant. Useful for allowing for cooldowns on more powerful abilities to be used to bring her down instead of automatic damage.
  • Charge! - Your allies take more damage, but so too does the Mother Plant.
  • Take a Breather - Allows your Sims to recover from infection while taking no damage. Use this just after firing off all your other cooldown attacks like Infection Vaccines and it may be the only tactic you need!
  • Warbling War Cry - repels the Mother Plant's Zombies
The mother plant is defeated in The Sims 4
The Mother is finished, and so is the story.

In general I didn't find much use in fighting Zombies but it very much depends on some randomness. I think they tie up your Allies while fighting but need to do the fight over a few more times. All in all get some damage in while minding your infection meter, using up your allies' infection vaccine cooldowns, and when around 40-50% infection level use Take a Breather. Depending how the fight is going you may want to switch to either Charge to finish her off, or Be Careful to make more use of your cooldown attacks.

A Mother Plant Friend

Making the mother plant your friend in The Sims 4
You can make the Mother Plant your friend

When you've beaten the Mother Plant, you're the Hero of Strangerville (reward trait) and will get cupcakes and mail from fans. Though you also get a few socials to retell the story of your heroics it's a fairly weak reward as it does not give Fame from Get Famous. However there is another reward hidden here.

Revive the Mother Plant with a Bizarre Fruit and you can begin to talk to her. Build up your friendship, which takes several hours at minimum, and the Mother Plant will start offering you things once you're in the green. At greater than 50% friendship she offers you four abilities, which all have a 24 hour cooldown. You can request energy, career success, riches, or life extension. The Mother Plant has her own page, which lists the benefits of her gifts.

StrangerVille Guides

StrangerVille Game Pack Guide
StrangerVille Town Guide
Military Career
StrangerVille Mystery Guide Act 1: Getting Started in a Strange Town
StrangerVille Mystery Guide Act 2: Evidence, The Dossier, and Key Card
StrangerVille Mystery Guide Act 3: Hazmat Suit, Spores and Spore Filter
StrangerVille Mystery Guide Act 4: Source of The Infection (Spoilers)
Story Guide (Spoilers) - Learn Things You May Have Missed - New
Source of the Infection
Sims 4 StrangerVille Mystery Guide Part 1 (Video)
Sims 4 StrangerVille Mystery Part 2 (Video) Ending the Source and Rewards
Cheats for StrangerVille

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Comments (5)

Sketch Eldersays...
The Hero of StrangerVille apparently gets free drinks and food at the bar and free curio items at the curio shop, including spy bugs and bizarre fruit. The curio shop items can even be sold from the hero's inventory if you want an easy source of cash. The free spy bugs are especially nice, since they make eavesdropping a free activity instead of a relatively expensive one.

Can the mother plant kill your sim? I read that she can, but wasn’t sure if that was true.

Mastah Burnzsays...

I'd just like to that any Spellcasters doing this will have an easy time when it comes to collecting the spores. I just went to The Secret Lab, scanned ONCE, and then used Copypasto to grab a bunch of spores from the ground. I already had 6 before doing this, and I now have 48. There doesn't seem to be a faster way for obtaining plenty of Bizarre Fruits, though. However, I believe they're growable with the gardening skill (you can take cuttings, anyway), so maybe literally farming them?


you can buy the fruit from the curio stand


I did my fight against the mother plant earlier today and mostly ignored the zombie too, but one did end up knocking out one of my team mates and then another had to go revive him, so there was briefly only 2 of us fighting her but it still worked out okay ☺️


Umm I did those steps but for somehow it doesn’t work:

1. I went to the secret lab

2. I found the amount of Spore clusters

3. I got 3 bizzare fruits

4. Somehow the chemical analyzer won’t work

Can you solve this problem? Thanks!

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