Variable scope issue

[Trek]

I have two plugins

Plugin 1 fires on hook: login_verify_success

Plugin contents:

global $tvbl;
$tvbl["var"] = "test";

Plugin 2 fires on hook: forumhome_complete

Plugin contents:

global $tvbl;
print_r($tvbl);

and it never has any data in plugin 2. Is vB doing something after a successful login that is clearing all variables, etc? I've tried several things, but can't seem to carry a variable over from the login_verify_success (where I need it) hook, once they log in.