One of the things that makes Dracula so scary (besides the blood-sucking, of course) is that he's foreign. Some critics think of Dracula as a kind of allegory about the collapse of British imperialism (check out, for example, Stephen Arata's article, which we link to in "Best of the Web"). According to that reading of the novel, Dracula's immigration to Britain represents a kind of invasion. Back in Stoker's day, folks worried that all the years Britain had spent colonizing and oppressing other cultures might, you know, have ticked some people off. The concern was that those "colonial Others" might come to Britain looking for payback. Stoker makes a big point of describing Dracula as emphatically foreign. His English is imperfect, he speaks with an accent, and he needs Jonathan's guidance when it comes to negotiating British cultural norms and legal procedures.
The Crew of Light is composed of an alliance of British, American, and Western European men in order to combat the Eastern threat, Dracula.
Dracula's invasion of Britain is reproduced on a smaller level in his "invasion" of Lucy's English home: his ability to victimize Lucy Westenra, the "light of the West," suggests the alarming ease with which he could potentially victimize the entire nation.