。
She's totally against my plan.
Literal
She [topic-は] my plan [to-に] [contrast-は] completely opposed is.
まるで ('completely, utterly, just like') here intensifies 反対 ('opposed') — 'completely opposed.' This adverb has a second life in similes (まるで...のように 'just like'), so context disambiguates: with an adjective or noun, it amplifies; with のように, it draws comparison. Note the particle stack には: に marks the plan as the target of opposition, and the contrastive は narrows the focus — 'as for the plan (whatever else she might agree with), she's totally against it.' This contrastive layering is a subtle but everyday feature of Japanese.