ルーシーは興奮して我を忘れた。

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

excitement; stimulation; agitation; arousal

obstinacy; atman; the self; the ego

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to forget; to leave carelessly; to be forgetful of; to forget about; to forget (an article)