This spell can't be countered.
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Return three lands you control to their owner's hand: Return Pearl Lake Ancient to its owner's hand.
9/20/2014 A spell or ability that counters spells can still target Pearl Lake Ancient. When one resolves, Pearl Lake Ancient won’t be countered, but any additional effects of that spell or ability will still happen.
9/20/2014 Any spell you cast that doesn’t have the type creature will cause prowess to trigger. If a spell has multiple types, and one of those types is creature (such as an artifact creature), casting it won’t cause prowess to trigger. Playing a land also won’t cause prowess to trigger.
9/20/2014 Prowess goes on the stack on top of the spell that caused it to trigger. It will resolve before that spell.
9/20/2014 Once it triggers, prowess isn’t connected to the spell that caused it to trigger. If that spell is countered, prowess will still resolve.