I am trying to implement a custom route, but getting a "No physical template file was found for template Index" error.

If I remove the custom route, and just load the document it works fine. But as soon as I add in the custom route I get this error.

When I debug at the controller, my model as a templateId and the template file does exist.

RouteConfig:

 routes.MapUmbracoRoute(
           "EventDetails",
           "programme/event/{id}",
           new{ controller = "EventDetails",action = "Index"},

           new EventDetailsHandler()
       );

Handler:

 public class EventDetailsHandler : UmbracoVirtualNodeRouteHandler
{
    protected override IPublishedContent FindContent(RequestContext requestContext, UmbracoContext umbracoContext)
    {
        var helper = new UmbracoHelper(umbracoContext);
        string alias = typeof(EventDetails).Name;
        IPublishedContent content = helper.TypedContentAtRoot()
            .First()
            .Descendants()
            .First(d => d.DocumentTypeAlias.InvariantEquals(alias));

        return content;
    }
}

Controller (not actually doing anything, tried just not specifing the controller and get the same result):

 public override ActionResult Index(RenderModel model)
    {

        //Do some stuff here, then return the base method
        return base.Index(model);

    }