S5E10: The D.E.N.N.I.S. System Season 5 admin — October 6, 2021 · 0 Comment It’s Always Sunny in Philadelphia: 5×10 The D.E.N.N.I.S. System Dennis presents his fool-proof plan for picking up chicks, but soon finds that the gang each has their own fool-proof plans for one-upping each other.