Chrono Trigger/The Queen is Gone

Chrono Trigger > Chapter 3: The Queen is Gone (600 A.D. first time)

Introduction
At this point you'll have both Crono and Lucca in your party. You should have gotten some cash from fighting monsters, so head to the market if you want and get some equipment, but otherwise your first goal will be to head into the cathedral. You should start getting used to using your different characters techniques to take out groups of monsters, as well as using double techs when you learn them which takes up both characters turns. Make sure you have some tonics, ethers, and revives if you want to be able to heal or restore your characters.

The Cathedral
Talk to each of the nuns, and talk to the upper left one then search in the middle of the room to find the missing coral pin the king mentioned. Note that you won't be able to do this until you have Lucca in your party. The nuns will turn into Nagaettes, and you'll have to fight them off. A strange froggy character will show up to save you from a surprise attack, and you'll get a chance to name him and have him join your party. We'll call him Frog for simplicity's sake, although like four of the main characters in the game, that's not his real name anyway. Play the organ to open up a new door when you're ready.

The next area is fairly straightforward. Go in a door up some stairs on the left side for a maidensuit, and check the egg like thing to the left of the chests to pick up the legendary naga-ette bromide, be prepared to fight some monsters. Go to the room above that one and flip the switch to find some soldiers and a power tab in the left pot.

The lower door on the right has some monsters chilling out, and if you wait one of them will leave to go into the top door to worship a statue of Magus they have set up. Follow him, pick up some items, and do battle with both groups of monsters. Remember you can have Frog use the slurp technique in or out of battle to heal you.

The next room is a little bit trickier. You'll need to walk around the whole thing one way or another since whatever stairwell you walk down first will turn into a slide. Flip the switch on the right side to open up a center passage where you first walked around, and play the organ there to open a north exit.

After heading down a short hallway, you'll see a door and a savepoint. Save and use a shelter, because the next room is the boss fight. Yakra has 920 HP but that's a lot at this stage of the game. I'd recommend having Frog heal with slurp when necessary, and using your best techniques or double techs. Try to keep your HP above 20 if you can help it. Once you've beaten him, check out the right chest for a Mid Ether, and you can choose to open the left chest depending on whether you want the real Chancellor to chase after you.

You'll end up back at the castle. Talk to everyone to hear some of their new dialogue if you want, and head to Marle's room to have her rejoin the party. Say goodbye to Frog, and you're ready to go. You also might want to rest to restore your health while you're there, it may still be depleted from the boss fight.

When you head back through Guardia forest, keep in that searching the same bush as you did before will you give a shelter each time you visit the area. Marle will have rejoined your party, so you may want to make sure she's got some good armor. Then head back to the mountain range to find a time gate which will take you back to 1000 A.D.

Challenging Lavos
Impossible during this stage of the game since you have no access to a time gate.

Continue to Chapter 4: We're Back! (1000 A.D. second time)