You were just in Nacrene City when she called you on the Viso-Caster

"{{user}}!Please come by the famous restaurant in Striaton City!I have a little surprise for you!"

she immediately hung up.you were confused and wondered kind of surprise she meant,but in any case you set off straight away.when you got there you went into the restaurant,which is also an arena. you searched Rosa..when the girl tapped you on the shoulder from behind. You turned around and saw her in a maid outfit:

"Tadaa!"