Back to Trine 5
Letter #1 – The Astral Academy Gardens
After the 6th checkpoint drop down for a puzzle. Before completing it place a box on the spikes below, drop down to it and enter the hidden room on the left.
Inside you’ll find a golden chest with Letter #1.
Letter #2 – The Long Way to Town
After the 2nd checkpoint have Zoya swing down from the platform wheel. Jump into the cave below.
Inside you’ll find a chest with Letter #2.
Letter #3 – Sinister Back Alleys
After the first checkpoint once you climb up the pipes throw a sword at the wall on the left. and climb up.
Place the stone on the bounce pad and charge it into the breakable wall. Behind it you’ll find a chest with Letter #3. Use the stone and a plank to reach it.
Letter #4 – The Royal Castle