Arc's Secret is a side quest in Mario & Luigi: Brothership that can be started on Shipshape Island after completing Rumbla Island. Read on for a full walkthrough of Arc's Secret, including its location, unlock requirements, and rewards.

Arc's Secret Location and Unlock Requirements

Arc's Secret Side Quest
Arc has been separated from his father for a long time. He acts like everything is fine, but it seems like something is on his mind. This is a limited-time quest
Unlock Requirements	Complete Rumbla Island
Quest Start Location	Shipshape Island

Limited-Time Special Quest

Arc's Secret is a special quest that must be completed before a certain point in the story. Once this quest is unlocked, it is highly recommended to do it immediately before progressing the main story any further.

Limited-time quests will disappear upon progressing the story, and you will be unable to complete them for the rest of your playthrough.

Defeat the Boss at Rumbla Island to Unlock

Side quests only start appearing in Concordia once you defeat the boss at Rumbla Island after completing both Raynforst Island and Twistee Island.

Arc's Secret can be started on Shipshape Island immediately once side quests become available.

Story Walkthrough

Recommended to Be Level 9

This side quest involves defeating enemies to complete it. It is recommended to have Mario and Luigi to be at least level 9 to easily complete this quest.

Arc's Secret Walkthrough

Arc's Secret Quest Objectives
Talk to Arc Go to Raynforst Island Fight the Invizilizard Pick Up the Sparkling Object Return to Arc on Shipshape Island

Talk to Arc

Upon approaching Arc and Connie after returning from Rumbla Island, a cutscene will start where they talk about the Great Lighthouse. Arc will start telling them about what happened to him and his dad, but will cut himself off.

After the cutscene ends, talk to Arc to trigger the Arc’s Secret side quest. Arc may move between the Uni-Tree and the Big Cannon if you don’t talk to him immediately. You can check your map for a thought bubble icon if you’re having trouble finding him.

Go to Raynforst Island

Before heading to Raynforst Island, it’s recommended to heal up if you’ve taken damage. Once you’re ready, use the blue pipe on Shipshape Island to fast travel to Raynforst Island.

Head northeast until you reach an intersection with two flower bridges. If you ask the Concordian in the middle of this fork if he’s seen a spyglass, he will direct you to the left flower bridge. Take this left bridge and follow the path until you find two Concordians talking to each other near an Invizilizard.

Raynforst Island Location Guide

Fight the Invizilizard

This Invizilizard is distracted by a sparkling object. Approach it, and Snoutlet will wonder if the gleaming object is the spyglass. Then, you’ll be able to do a first strike by pressing A.

Defeat the hoard of level 8 Invizilizard using your Jump and Hammer attacks or your new Bros. Attack.

List of All Enemies

Pick Up the Sparkling Object

Once all the enemies have been defeated, interact with the sparkling object by pressing the A button.

Return to Arc on Shipshape Island

Take out your Return Pipe by pressing ZR, and use it to go back to Shipshape Island. Arc should be in front of the Uni-Tree, but you can also check your map for the side quest thought bubble icon with a check mark to find his exact location. Talk to Arc to complete the quest and get your reward.

Arc's Secret Rewards

Arc Scope Accessory

Reward	Description
Arc Scope x1	Increases EXP earned by 15% if you win a battle without taking any damage. SPEED +2

Completing the Arc’s Secret side quest rewards you with the Arc Scope accessory, which can increase EXP earned from battles when equipped as long as the brother holding it doesn’t take damage.

List of Accessories

Mario & Luigi: Brothership Related Guides

All Side Quest Locations

Lushgreen Sea Side Quests

Color-Full Sea Side Quests

Brrrning Sea Side Quests

Gulchrock Sea Side Quests

Stormstar Sea