Upper wing, right
Step 1 / 5
u': Top inner layer: turn 90°, front face goes right
The front right edge has its middle piece and lower wing matching. The missing wing is high on the front left edge; its left color is the pair's front color.
u' brings the wing over, R U R' stores the edge on top, u undoes the slice.
Step 1 of 5: u'. Top inner layer: turn 90°, front face goes right