Mass Effect 3 Irune: Book of Plenix Guide—Where to Find and Start the Quest

If you’re working through Mass Effect 3 and trying to locate the Irune: Book of Plenix, this guide page breaks down exactly how to start the side mission, where to travel, and what to do once you actually find the book. It’s also organized so you can jump straight to the section you need.

Checklists

  • Mission Stats
  • Travel to Widow
  • Meet the Volus
  • Find the Book of Plenix
  • Return the Book of Plenix

Mission Stats

Video Guide

Mission Rewards

  • Reputation: +5
  • Mission Credits: 15,000 credits
  • War Asset: +40 TMS to Citadel Defense Force

Travel to Widow

  • Prerequisite: Complete “Priority: Palaven”
  • Location: Serpent Nebula – Widow – Citadel – Citadel Embassies

This side job won’t show up until after you finish “Priority: Palaven,” which also opens up the Presidium Commons area on the Citadel. If you haven’t navigated to the Citadel on your own yet, it functions as the galaxy’s main hub, and it will always be indicated in the western side of the Milky Way on your map.

Meet the Volus

  • Prerequisite: Complete “Priority: Palaven”
  • Location: Serpent Nebula – Widow – Citadel – Presidium Commons – Bank

Once “Priority: Palaven” is complete, you’ll gain full access to the Citadel, including the Presidium Commons. In the far western portion of the commons, you’ll find the Bank. Head to the back-left corner of the room and check the couches—there you’ll locate a volus talking with a seated salarian. Pay attention to what the Volus says; after that, the quest will eventually appear in your Journal.

Find the Book of Plenix

  • Prerequisite: Complete “Priority: Tuchanka”
  • Location: Aethon Cluster – Aru – Irune

Even though this side mission can start relatively early in the game, the star system tied to the Book of Plenix doesn’t become available until after you complete “Priority: Tuchanka.” When it unlocks, travel to the Aethon Cluster, just off the “southwestern” edge of the Milky Way.

In the Aethon Cluster, you’ll dock in the Aru system, which is convenient because Irune is located there. Irune is the second planet in the system, sitting “north” of the star. Scan the planet to verify there’s something worth investigating, then select it. Bring up the Scanner, follow the white marker to the point of interest, and fire a probe. That action will let you recover the Book of Plenix.

While you’re in the Aethon Cluster, it’s worth spending a little extra time checking around—this area includes multiple Search and Rescue collectibles, not just the book you came for.

Return the Book of Plenix

With the Book of Plenix in hand, head back to the Citadel and return to the Bank section of the Presidium Commons. The Volus will still be there, ready to take the book from you and finish the quest.

Want more Mass Effect 3 help? Check out the following pages:

  • Legendary Edition Changes
  • How-To Guides
  • Key Choices and Consequences
  • Romance Guide
  • Walkthrough
  • Side Missions

Up Next: Kite’s Nest: Pillars of Strength

Top Guide Sections

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Marcus Chen is a gaming journalist and industry reporter with more than 10 years of experience. He covers releases, announcements, and trends across PC, PlayStation, Xbox, and Nintendo, and keeps a close eye on the indie scene and esports. Previously an editor at several gaming publications, he now writes news, reviews, and breakdowns of major industry moments—from big showcases to updates on popular titles. His work is aimed at players who want a clear, fast read on what happened and why it matters.