How do I "pass the request directly to the script with parameters "?

server {
listen 80 defaultserver;
listen [::]:80 defaultserver ipv6only=on;

root /var/www/example/html;
index index.php index.html index.htm;

errorpage 404 /404.html;
errorpage 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}

location = /favicon.ico {
lognotfound off;
access_log off;
}

location = /robots.txt {
allow all;
lognotfound off;
access_log off;
}

location ~ ../..php$ {
return 403;
}

location ~ ^/sites/.*/private/ {
return 403;
}

location /wordpress {
return 403;
}

location /getmoreinfo {
return 403;
}

location /fckeditor {
return 403;
}

location /teaching-artist {
rewrite /teaching-artist/(.)$ http://example/teaching-artist/$1;
}
location /print/content {
rewrite /print/content/(.)$ http://example/print/content/$1;
}

location /content {
rewrite ^/content/([^]*)([^]*)([^]*)([^]*)([^]*)([^]*)([^]*)([^]*)(.)$ http://centerforartsed.org/mediaclips/$1-$2-$3-$4-$5-$6-$7-$8-$9;
rewrite ^/content/([^_])([^])([^])([^])_(.)$ http://example.org/mediaclips/$1-$2-$3-$4-$5;
rewrite ^/content/([^]*)([^]*)(.)$ http://example.org/mediaclips/$1-$2-$3;
rewrite ^/content/([^_])_(.*)$ http://example.org/mediaclips/$1-$2;
}

location /wpadmin {
return 403;
}

location ~ (^|/). {
return 403;
}

location / {
try_files $uri @rewrite;
}

location @rewrite {
rewrite ^ /index.php;
}

location ~ .php$ {
fastcgisplitpathinfo ^(.+.php)(/.+)$;
include fastcgiparams;
fastcgiparam SCRIPTFILENAME $requestfilename;
fastcgiintercepterrors on;
fastcgipass unix:/var/run/php5-fpm.sock;
}

location ~ ^/sites/.*/files/styles/ {
try_files $uri @rewrite;
}

location ~* .(js|css|png|jpg|jpeg|gif|ico)$ {
expires max;
lognotfound off;
}
}

If it helps any Googlers, I just set the 404 in Drupal UI and then commented out the line

error_page 404 /404.html;

which I found in /etc/nginx/sites-available/ in a file called drupal

I then did 'service nginx restart' and it worked.