Defeat the Orcs and proceed right over the lava flow using the LEGO platforms to cross it. Use the LEGO Grab Ledges to climb to the upper platform and proceed right.
Continue moving right and, as Isildur, attack the Morgul LEGO blocking the path. From here cross the lava flow via the LEGO Platforms, avoid the volcanic blast vents and smash the Morgul LEGO beyond.
Use the LEGO Grab Ledges to shimmy right over the lava and smash the Morgul LEGO supporting the LEGO Balance Beam. Then defeat the Orc’s that emerge from the cave, and climb the up the beam.
Switch to Elrond (2nd Age) and move to the Elven Leaves Marker and jump to the high platform above. When on top, push the large LEGO Boulder into the lava and switch to Isildur who can now use the LEGO Boulder as a platform to cross the lava.
Continue heading right and jump up to the LEGO Grab Ledge at the back of the platform. Once achieved, jump up to the raised platform and defeat the Orc’s that appear there until the gate opens. Then proceed through the open gate and head to the end of the platform.