Tom and Bud wore swimming trunks under their slacks. Unfortunately the girls had forgotten to bring their suits. When the _Sunspot_ reached the center of the lake, the boys hove to, stripped down to their trunks, and dived overboard. Meanwhile, the girls sun-bathed on deck. Soon it was time for the picnic lunch, and all four ate with healthy young appetites. "Jeepers!" Sandy whispered to Phyl with a giggle. "After a feast like this, we'll have to go on a diet!" "Don't say it," Phyl warned, "or Tom and Bud will use that as an excuse for never taking us out ag--" She broke off with a gasp. "What's wrong?" Tom asked. Breathless with fright, Phyl pointed off to starboard. The others paled. An enormous wave was sweeping across the lake, straight toward the ketch! "Jumpin' jets!" Bud gulped. "It's like a tidal wave!" The boat was already rocking under the swells that preceded the oncoming huge breaker. "Quick!" Tom yelled. "Grab life jackets while I start the engine!" The four leaped into action. Every instant the terrifying wave rushed closer! By now it was a twelve-foot wall of water! Tom and the others had just put on the jackets and the engine had barely gunned into life when disaster struck. The mammoth wave swept up the _Sunspot_ and heeled it far over into the trough like a toy bark. The next instant a cataract of water poured over the deck with stunning force! "We're going under!" Phyl screamed. All four were swept overboard in the maelstrom! Under the smashing impact of the water, the ketch's mainmast bent and groaned. A moment later came a crack like a gunshot. The mast broke off, hung teetering by shreds, then toppled into the water. As it fell, the mast struck Sandy a grazing blow on the head! "Sandy!" Bud cried fearfully as he struggled in the swirling torrent. Calling on every ounce of strength, he swam with powerful strokes toward the girl. Sandy was dazed and limp. Bud's husky arm circled her tightly. Then he began to fight his way toward shore. Tom and Phyl--each struggling in the turbulent water--could only breathe a prayer of thanks as they watched the rescue. [Illustration (a huge wave capsizes the Sunspot)] As the huge wave raced shoreward, the lake water gradually became calmer in its wake. Tom was able to assist Phyl, and Sandy by now had recovered her faculties. The _Sunspot_ had capsized but could still be seen afloat, some distance away. Rather than swim to it and cling to the hulk in the hope that a rescue boat would arrive, the four decided to continue on toward shore. They knew that the aftermath of the tidal wave would keep all shore facilities in an uproar for hours to come. As they neared the beach, the young people could see other overturned craft and heads bobbing in the water. A few daring persons finally began putting out in motorboats and rowboats to pick up the survivors.