Peter Massey-Plantinga

A conditional two-level menu only shows the second level of the menu on relevant pages.
For example, if you had a menu that had a structure like so:
<ul>
<li>Home</li>
<li>About
<ul>
<li>History</li>
<li>People</li>
</ul>
</li>
<li>Contact
<ul>
<li>Mail</li>
<li>Phone</li>
<li>Email</li>
</ul>
</li>
</ul>
You would only be able to see the “History” and “People” menu items on the “About,” “History,” and “People” pages.

Two Level Conditional Menu

This plugin converts a two-level menu to a conditional two-level menu.

sevenspark

Bellows is an awesome accordion menu for WordPress. It works with the WordPress menu system to allow you to build beautiful accordion menus for your site.
<a href="https://wpaccordionmenu.com/free/" rel="nofollow ugc">Bellows Lite Demo</a> 
<a href="https://wpaccordionmenu.com/" rel="nofollow ugc">Bellows Full Demo</a>
Get started: <a href="http://sevenspark.com/docs/bellows/quick-start/lite" rel="nofollow ugc">Bellows Quick Start Guide</a>
<h4>Feature Overview</h4>
<ul>
<li>Fully functional accordion menu</li>
<li>Multiple submenu levels</li>
<li>3 included skin presets</li>
<li>Multi- or single-folding</li>
<li>Expand current submenu automatically option</li>
<li>Shortcode integration – add an accodion menu to yoru site anywhere you can add shortcodes</li>
<li>Widget integration – add an accordion menu to your widgetized theme areas</li>
</ul>

Bellows Accordion Menu

A flexible and robust accordion menu plugin

Two Level Conditional Menu vs Bellows Accordion Menu