Bootstrap 4 and MVC5 open modal as partialView - asp.net-mvc

Question

I have read this post and it fires the modal but not quite.
I just see grayed window but I don;t see modal.
My HTML:
<div id='gameModal' class='modal hide fade in' data-url='#Url.Action("TermsAndConditions","Base")'>
<div id='gameContainer'/>
<button id='showGame'>Show Game Listing</button></div>
In my js:
$('#showGame').click(function () {
var url = $('#gameModal').data('url');
$.get(url, function (data) {
$('#gameContainer').html(data);
$('#gameModal').modal('show');
});
});
And I've created a controller as well with a partialView:
[HttpGet]
public ActionResult TermsAndConditions()
{
return PartialView();
}
I found that line in my js file is skipped: $.get(url, function (data)
probably because I have additional parameter in my routing config.
Instead of "normal" routing such as "/Base/TermsAndConditions" I have
"/en-US/Base/TermsAndConditions"
Any hints how to set url without additional parameter without splitting the urls and mambo-jumbo things?
Here is my routing config:
public class RouteConfig
{
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute(
name: "Default",
url: "{language}/{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional, language = "en-US" }
);
}
}
Is there any more modern approach for openning modals with partialViews?
UPDATE:
I've managed to view my modal, but only if I put partial view HTML code beside my button in my for example layout page like this:
<button class="btn btn-primary" data-toggle="modal" data-url='#Url.Action("TaC","Home")' data-target=".bs-example-modal-lg">Large modal</button>
<div class="modal fade bs-example-modal-lg" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
<div class="modal-dialog modal-lg">
<div class="modal-body">
<div class="modal-content">
<div class="modal-header">
<h4 class="modal-title" id="myModalLabel">Modal Heading</h4>
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
</div>
<div class="modal-body">
<p>Praesent commodo cursus magna, vel scelerisque nisl consectetur et.
Vivamus sagittis lacus vel augue laoreet rutrum faucibus dolor auctor.</p>
<p>Aenean lacinia bibendum nulla sed consectetur. Praesent commodo cursus magna, vel scelerisque nisl consectetur et. Donec sed odio dui. Donec ullamcorper nulla non metus auctor fringilla.</p>
</div>
</div>
</div>
</div>
</div>
If I put data-url=#Url.Action("Index","Home") it not goes to the controller.