Aside from the fact that the expedition started out in a cloud of confusion and vagueness, it seemed that the journey might come to an end before it could even see a battle. Close to the departure of the fleet, there occurred one of those rare events that would be ludicrous if their consequences had not been so dire.
In the course of the night, certain public statues, more specifically those of Hermes, the god of good luck and fertility, were defaced throughout the city. The Athenian people were devistated and saw it as a bad omen for the expedition. Although an investigation committee was unable to discover a guilty party, witnesses claim that Alcibiades had openly mimicked the initiation rites of an official, Athenian, secret religion, the so-called Eleusinian mysteries, associated with the worship of Demeter and Persephone [5]. Despite the strong suspicion surrounding Alcibiades, the fleet was ordered to depart as planned. However, shortly after they set sail, an Athenian state ship caught up to the fleet and arrested Alcibiades, who was then removed from the expedition. 
Now, the very creator and instigator of the expedition was no longer involved, and prospects started to look dark for Nicias and Lamachus. Alcibiades' mocking attack on Athenian culture should have been a warning of events to follow. If Acibiades could not even retain respect for the empire he was sending into war, how could the Athenian people believe that he could serve as a true representation of their civilization outside of Greece and could they even trust him? This poor judgement of character on Athens' part became one of the deciding factors in the fate of the expedition, because not only is the main general now out of the picture, but he managed to escape from the Athenian ship. And to make matters worse, Alcibiades swam to the Peloponnese shores and proceeded to tell the Spartans every detail of the expedition. Besides the expedition just being encompassed in confusion and vagueness, it was now completely vulnerable to its enemies.
Now with Nicias, known as a terrible general, in charge, the possibility of success was becoming less and less of a possibility. But a surprising turn of events boosted the morale of the Athenian army, for at least a short amount of time. As the Syracusans became aware of Athenian presence, they set a date to take over their camp in Catana. Luckily, Nicias was aware of this plan and managed to carefully pass the Syracusan army. In a battle that followed, the Athenians routed the Syracuse back into their city and seemed to have gained a small victory. But then Nicias packed up his army and headed back to Catana. Nicias' decision to fall back rather than defend this skillfully won position over the enemy proves just how horrible of a general he really was. The only thing that these little victories did was convince the Syracusans that the war was not going to be won so easily.
Although it may have seemed that Nicias was actually making some progress in the war with these little victories, his tendency to hesitate and procrasinate caused bad decision making leaving his forces to slowly die-off. 
After awhile, Nicias was hoping that the bad news of the war would reach home and Athens would demand their return. Instead, they sent 15,000 more men under the command of a dynamic general, Demosthenes [6]. To try and jump start the war, Demosthenes tried an immediate offensive, but this failed. Demosthenes gave up hope and wanted to withdraw the entire force safely while they still could, but Nicias, who feared punishment in Athens for trying to escape, was hesitant to agree. After assessing their supply and water levels, which were dangerously low, Nicias finally agreed to try and leave. Following the Athenian tradition of bad omens, the night they were supposed to leave, there was a total lunar eclipse. The religious officials among the Athenians declared it an evil sign and decreed that the arm wait until the next full moon, which was many days from then. Now the Athenians had lost their only chance to escape [7].
When the Syracusans heard that the Athenians were trying to escape, they caught them by surprise and bottled the Athenian fleet in the harbor and destroyed and captured their entire fleet. Nicias and his army had no choice but to take to land across Sicily to an Athens-friendly port to find some ships to sail home. But the army had already been suffering from diseases contracted in the swamps outside of Syracuse, and the enemy was dogging their every step. When scouts reported a river ahead, the army broke out into a mob and ran for it. As the Athenians tumbled into the small river, the Syracusans, who had been waiting for them on the opposite bank, attacked them. Much of the army was slaughtered, and most of the rest were captured and enslaved; only a handful ever made it back to Athens. As for our brave generals, Nicias and Demosthenes, they surrendered and were put to death [8].
