。
She showed up in the kitchen.
Literal
She [topic-は] kitchen [at-に] appeared.
現れる ('to appear, show up, emerge') is the standard intransitive verb for someone or something coming into view. Takes に for the location of appearance — に for the destination/locus of the appearing motion. Compare 出る ('to emerge, exit'), which is more directional, and 来る ('to come'), which centers on motion toward the speaker.