。
She came here to shake out the dust.
Literal
She [topic-は] dust [object-を] shake-off [in-order-to-ために] here [at-に] gathered.
A grammatically unusual sentence. 集まる ('to gather, assemble') is intransitive and typically takes plural subjects — many people gather together. Pairing it with the singular topic 彼女は ('she') strains the verb's natural meaning; you'd more often expect 来た ('came') or 集めた (the transitive 'gathered [things]'). The intended sense is 'she came here in order to shake out the dust,' as the rest of the structure makes clear: ~ために marks the purpose, and the destination ここに ('here') and verb 集まる sketch out arrival. The structure is worth noting as a learning point about subject-number constraints on intransitive 集まる — pairing it with a singular subject reads as either highly unusual or genuinely off-grammatical.