Where to get this case:
When you walk around at night, you will at some stage notice a "Buzz!!" blinking above the minimap.
Open the Buzz with the right arrow button and you will see where the Buzz is at the map.
That's when the Side Case starts.
FIND THE ROAMING BODY MODEL
Go to Seiryo High School.
The starting point is near the MRC.
On the second floor, enter Observation Mode and choose the AMP to find it.
Then chase and catch it.
SPEAK WITH NAITO
Next time you see "Body Model" Naito, speak with him. You will have to wait until morning at school.
He's in the cafeteria on the first floor.
SIDE CASE CLOSED