The low entrance chamber has two too-tight passages to the left that can take some of the water. The route down to the right reaches walking passage to a 3m climb up out of the stream and a once-tight squeeze into a chamber with calcite columns. To the left, a stooping passage rises to a choke, with a tighter route to the right which chokes to the left but continues down, unexplored.

Northern Passages
   The main passage swings to the right, passing along a short traverse. At the base of the traverse, the downstream route is too tight. Over the top, and to the left, a false-floored passage soon chokes over a 10m-deep drop which is too tight about 3m down. Beyond a squeeze, further holes link down to El Dia del Padre Series. Some fine sediment banks are encountered with a climb up and over to the north into a route that has been excavated through a short, body-hugging crawl. After a total of 30m, the passage meets a cross rift with a crawl to the east appearing to get too low.
   Back in the main passage, beyond a squeeze past formations, the cave lowers to a flat out crawl, entering larger passage on a bend. After a further 15m, at survey station 10, the passage divides at two 3m climbs down.
   The laddered climb down to the north enters a nicely shaped vadose passage which meets a hammer and chisel dig, after turning south - close to the main route already traversed.
   The eastern climb encounters boulders and, continuing east, eventually chokes in all directions, with avens at the end of the passage after it has swung around to head south. Part way down the eastern climb, a passage heads off to the northwest to encounter, after an excavated squeeze, a sloping climb below a chamber with stal. A ladder is required on this 4m muddy, sloping drop.
    At the bottom a low streamway is met that has been pushed in neoprene both up and downstream. An angular passage heads downstream for about 20m almost identical in character to the streamway in Cueva de la Loca 1. This goes around several bends to a low duck under roof pendants. The passage 'ends' immediately afterwards at a mud barrier blocking the passage completely (apart from a small bit of airspace above it). It could be dug by bicycle kicking it. Upstream starts with a flat out wriggle in the water and then became similar to the downstream. Several corners are negotiated until no more progress could be made: the passage was again blocked with mud in the floor, but this time there was enough space above it to slide oneself up into a narrow rift and look into a small but dry chamber ahead, with a loud sound of falling water. This might be accessible once the mud has been removed, but it is very possible that the rift will still be too tight.

   El Dia del Padre Series
   Back at the chamber with calcite columns near the entrance, the route to El Dia del Padre is down a short drop, laddered from one of the larger stalagmites. This immediately meets the stream coming from the entrance, with a 15m-long, dry crawl over tufa-encrusted detritus to the left. The crawl emerges at an enlargement - a small unclimbed aven, a crawl downstream to the north to an incompletely explored and unsurveyed section, and a short traverse south to a low, bouldery chamber. Below the traverse, the passage meets water, which must be a different stream from the one in the entrance passage, but possibly comes from a separate sink somewhere in the entrance shakehole.

   The low, bouldery chamber is a hub with at least 3 routes out:
   (1) Ahead, to the east, the route emerges near a cross rift which chokes in both directions. After crawling under sediment to the north, the passage enlarges with holes in the roof where a larger passage is seen. These are the holes down between boulders seen near the sediment bank in the Northern Passages.

   (2) There is a route down to a passage at the S side of the low chamber which meets a hole down on the right of the eastern route. (Batch 24-12). After passing a sediment bridge and a boulder bridge, the route narrows over boulders, then meets water. Walking upstream to the west finds the water emerging from a low, wet bedding which has yet to be explored. To the south, a small step up at station 24-12.17 (marked with pottery and old bones found in the stream) leads to crawling and stooping over mud with water sometimes seen in a trench. After squeezing up and around to the right of a stal boss, the bouldery route is again over a small trench. Current progress along the passage has stopped at a low, wide crawl over fallen roof slabs. Some digging is almost certainly required. No draught was noticed.

   (3)  Beyond the low bouldery chamber, the passage enlarges to the west, encountering ancient gravel deposits on the walls then a short stoop over a stream in a well-decorated section. A short crawl then emerges at a T-junction. The 2m-high passage quickly closes in to the east where a dig to the right may link with passage to the south and a possible dig to the east is just too low for as far as a camera will go (video). The western route from the T-junction passes a floor stal and an alcove with fine, orange and grey banded sediment. Varied going bypasses a decorated hole with a route past choked holes down to the north. The walking route ends at muddy holes above, entered using combined tactics.
    At the top, in a decorated chamber, a walking route to the north passes a pit and becomes too small as it turns east then south. The chamber contains a 5.4m deep pit with a possible small, high-level passage heading south. Down to the north, over some large slabs, a crawl and a climb up over stal reaches the other side of the pit, with choked areas with holes above and below.
    At the west side of the pit, a small passage ends at 2 holes in the floor, the western one big enough to drop down then traverse to another step down into walking passage. Passages choke at low level or rise up to meet chokes close to the surface. Daylight is seen to the west and a short, roomy crawl emerges out of site 5401, on the side of a vegetated depression - the next shakehole to the west of the first entrance. Site 5401 was unknown until discovered from inside the cave.
   About 12m to the SE of #5401 lies choked cave 5404.