Saving the second spy is not complicated, but requires timing. Go to the building on Toupee Terrace that has electrified doors and windows. Jump up to each window while the power is off. When you reach the roof, use the Laser Pen to cut open the bars. Go inside and untie the second spy. He will give you the Grapple Bowtie.
You have to rescue the three spies in order, because the first spy gives you the item to rescue the second spy, and the second spy gives you the item to rescue the third spy. The first spy is in the warehouse at the Docks, the second is in the electrified building on Toupee Terrace, and the third spy is in a greenhouse on the Rooftops above the Grease Monkey garage. (see related questions)
Go to the electrified building on Toupee Terrace and rescue the second spy.
You have to rescue the three spies in order, because the first spy gives you the item to rescue the second spy, and the second spy gives you the item to rescue the third spy. The first spy is at the Docks, the second in the electrified building on Toupee Terrace, and the third on the Rooftops above Balding Avenue. (see related questions)
You need the Laser Pen. The spy in the attic is the "second spy" to rescue, because the first spy you rescue has the Laser Pen. Get the Chameleon suit from Spyglass Eyewear, and rescue the first spy on the docks. Then you can come back to the electrified building and save the second spy. (see related questions)
You get the laser pen from the first rescued spy (at the docks), and use it to rescue the second spy (in the electrified building on Toupee Terrace). The second spy gives you the grapple bowtie, which you use to rescue the third spy on the rooftops above Balding Avenue.
No. You get it when you rescue the second missing spy. The first spy is at the docks and you require the Chameleon Suit. The second spy is on Toupee Terrace and you will need the Laser Pen (from the first rescued spy). The third spy is above Balding Avenue, so you will need the grappling bowtie to rescue her.
To rescue the second spy, avoid the electrified windows. To rescue the third spy, you will need to go up one building to the rooftops, then to the far left and back again. This requires the Grappling Bowtie from the second spy. (see the related question)
You get it when you rescue the first kidnapped spy, at the docks. You have to rescue the three spies in order: the first one gives you the laser pen to rescue the second one, and the second one gives you the grappling bowtie to rescue the third one. (see related question)
From the second spy you rescue.
Rescue the third spy from the Rooftops above the Grease Monkey garage. You will need the Grapple Bowtie from the second spy. (see related questions)
You can't. The quest includes climbing ABOVE the garage after you rescue the second spy. (see related question)
To rescue the three kidnapped spies on Spy Island, you have to get them in order, because the first has the Laser pen to free the second one, and the second one has the rappling Bowtie to rescue the third one. (see the related question)