The World Ends with You/Day 3: Who 2 Trust

You will start in the dark Concert Stage. Walk around for a bit and you'll find Shiki.

Obtain (S) Shutdown, (B) Shutdown and (S) Easy mode.

Right now, you will see a scene with a new person named Sanae Hanekoma. Ask him everything on the chart and then after, leave the place down south.

A-East
Right there near the entrance,you will meet a rock star named 777 (Porcupine). He needs help, so...help him.

Also, if you have some yen, go to Lapin Angelique and buy some clothes for Phones (that will be Neku) and Shiki. You will obtain (B) Shop Clerks and Item Abilities.

From there, go down south and talk to the Reaper. You will then be in a tutorial about Shiki's Fusion.

Fusion is basically a special attack used by both characters, but needs a certain amount of stars to use it. For Shiki, three ESP cards will appear. You have to guess which card is which by navigating through the combo map to get to the card you want to guess. If right, you get a star. If right without fail, you get two stars. If you're wrong, there might be a chance that the card you guessed will flash, so keep trying. Once you get enough stars, a pin will appear in Neku's screen. Touch it to deal damage and restore a bit of HP. After the fight, you will get (S) ESP Cards and (S) Fusion Boost.

Now exit at the bottom.

Dogenzaka
Scan in the bottom left corner to reveal a Green Noise. Defeat it for 500 yen.

Go right, enter and Ramen Don will find Porcupine's Tech, Futoshi. Before you go, take a look on the foods, remember you can eat these foods to increase your stats. But you may save your money for now since it's a bit expensive here.

Futoshi will appear in Dogenzaka. Now scan him and surprisingly, an Orange Noise symbol will appear in a weird way in his thought bubble. Touch the Noise to battle it. After, he snaps right out of it and runs back to A-East. You will get (S) DEF Boost, (B) Red Noise Symbols and (B) Yellow Noise Symbols.

A-East
Porcupine gets angry and sick of yelling, so talk to them, then head north to find a Reaper. Defeat the two Noise symbols he wants and the wall will be cleared and you will get (S) Jump and 5,000 Yen.

Shibuya main store
You will meet Skulls (still angry at Phones) and Rhyme. They'll teach you about memes and imprinting ((B) Memes and Blackout meme). Test it on "Shrimp" (the guy in the suit's name is unknown).

After, Futoshi will still be around, so imprint him with "blackout." He hints about a person in the concert stage, so head back there.

Before you go, you can defeat a Green Noise for 5000 yen near the left of this place.

Concert Stage
Go to the top right and scan to find a thought bubble. Read it to get the meme "Fuse."

Go to Dogenzaka to get two more memes. "Cough drop" can be obtained by scanning the girl standing near Cosmic Corner. "Ramen" can be obtained by entering Ramen Don.

Go back to the Shibukyu Main Store and imprint Futoshi with "Cough Drop". Follow him to Dogenzaka and enter Cosmic Corner. After the scene, imprint him with "Fuse". Enter Cosmic Corner again.

Now go to A-East and talk to Porcupine to end the job. You receive a 'Lucky Star' pin as a reward. Now save, adjust your pins and head to the Concert Stage.

Go to the top right to hear Futoshi and that will send you into a boss fight.

Boss

 * Vespertilio Canor: Level 6

Suggested pins:
 * Healing Can
 * Force Rounds
 * Ice Blow

The boss usually appear on the Neku screen, so Shiki will face the bats which allows you to open the ESP Cards easily. Catch every chance to hit the boss when it shows up; it's advised to use long-range attacks. Once you get all the ESP Cards, quickly perform the fusion, and it could probably stun the boss, giving you more chances to hit him.

Obtain (S) ATK Boost, Poison Bones, Scarletite.