An underground complex, which was composed of several adjacent ancient chambers connected by narrow winding tunnels, was documented. The entrance to the complex is by way of a rock-hewn corridor (A; c. 1.8 × 7.0 m; Figs. 2, 3). Three openings in the walls of the corridor lead to underground chambers (B, D, E). The plan of the corridor and the chambers resembles a clover-leaf, and is characteristic of sites in the Judean Shephelah from the Hellenistic and Early Roman periods (Kloner and Zissu 2013:50, 52). An entrance (width 1 m, height c. 2 m) with a hewn stepped lintel at its top was opened in the northwestern wall of the corridor, and led to Chamber B (6.4 × 8.0 m; Fig. 4) through a rock-cut staircase. Later quarrying cut through the fourth step of the staircase. The floor of the chamber was lowered, and the space was apparently converted into a quarry. Most of the floor was covered with collapsed debris and alluvium, and it was therefore difficult to determine the original height of the chamber (average height c. 4 m from the top of the alluvium layer to the ceiling). The southwestern and northeastern walls of the chamber are convex, and remains of two high arcosolia are visible on either side of a rock pillar in the northern wall; the arcosolia and pillar were probably removed when the chamber was turned into a quarry. A niche (length c. 1.2 m, depth 0.8 m) was cut into the eastern arcosolium. Two adjacent niches where cut into the northeastern wall, and two tethering rings were drilled next to them; the niches were probably used as troughs for donkeys. A broad vaulted doorway (width c. 1.8 m, height c. 3 m; Fig. 5), its upper part enclosed within a frame with a smoothed surface, was opened south of the niches. It leads to a rock-cut chamber (C; diam. c. 3.5 m) with an opening in its ceiling, which leads to another chamber (F) on a higher level. Two niches (length 1.1–1.2 m, depth c. 0.4 m) flanked the opening in the southeastern wall of Chamber B. A cross, with the Greek letter Π above it, were engraved below the eastern niche. Similar niches were constructed in the southwestern wall of the chamber. A later breach in the southeastern corner of Chamber B, connected that space to Chamber E. The architectural plan of Chambers B and C suggests that they were originally used as a subterranean oil press. Two beam-and-weight presses were installed in the arcosolia in the northern wall of Chamber B. The presses and the pits in which the weights were placed were removed when the facility was converted into a quarry, perhaps during the Byzantine period. The small niche in the northern wall is a remnant of the installation, and the base of the wooden beam of the press probably slotted into it. Presumably the olive crusher was situated in Chamber C, which is circular. Oil-press installations with similar plan were found in the lower city at Maresha, where they were dated to the late third century–second century BCE (Kloner and Sagiv 2003:41–72). A similar underground complex from the Early Roman period, with a corridor leading to a series of chambers arranged in a clover-leaf plan, was excavated at nearby Horbat Bet Loya. The main chamber in the complex functioned as an underground oil press. It contained a beam-and-weight press, and had a circular side-room, which contained a crushing installation. The complex was later converted to a quarry, and its floor was lowered by about 3 m (Gutfeld 2009; Gutfeld and Kalman 2010:175–178). Similar underground oil presses are known from sites in the Judean Shephelah, such as Horbat Hazzan, Horbat Shem Tov and Khirbat Khallat Qays (Kloner and Tepper 1987:115–118, 194–197, 226–231, 240–242; Klein and Klein 2015). This type of oil press remained in use in the Judean Shephelah after the destruction of the city of Maresha and during the first century BCE and the first century CE; thus it is not possible to determine if the installation at Horbat Ezra dates to the Hellenistic or the Early Roman period. Some pottery was collected in Chamber B, including two jar-stands from the Hellenistic or Roman period (Fig. 12:6, 13), a fragment of flask characteristic of the Early Roman period (Fig. 7:10) and a fragment of cooking pot characteristic of the period between the first century CE and the time of the Bar Kokhba uprising (Fig. 6:7). A fragment of a chalk basin (Fig. 7:16) was also found. 
An opening (width 0.7 m, height c. 2 m) in the northwestern wall of Corridor A led to Chamber D, which was a bell-shaped cistern with a spiral staircase and railing (Fig. 8); similar cisterns were common in Maresha and its vicinity in the third–first centuries BCE (Kloner and Zissu 2013:58). The cistern was filled from an opening in the ceiling, through a narrow channel that connected it to Corridor A. Two hiding tunnels (d-d, e-1), and yet another tunnel in an inaccessible location, breached the upper part of the cistern and apparently facilitated access and clandestine drawing of water when the hiding refuge was used, probably during the Bar Kokhba uprising. Hiding refuges with similar plan, which allowed water to be drawn secretly, were discovered elsewhere in the Judean Shephelah, for example, at Horbat ‘Amuda, Horbat Midras, Horbat Qanim (Kloner and Tepper 1987) and Horbat Shuweika (Zissu 2000:71). Tunnel d-d (length c. 6.5 m, width c. 0.7 m, height 0.85 m) was hewn through the northwestern wall, at the level of the top step of the cistern. It continued to the north for c. 1.5 m, and then turned 90° to the west; at this point the tunnel breached the southwestern corner of nearby Chamber B, connecting it to the cistern. A cross is engraved over the opening of the tunnel, and above it the Greek letter Π (Fig. 9).
A doorway in the northeastern wall of Corridor A leads to Chamber E (c. 4.5 × 5.0 m). The floor of the chamber was covered with alluvium, stones and a large quantity of pottery, including jars (Fig. 6:1–11), cooking vessels (Fig. 7:1–5, 7, 8), a flask (Fig. 7:9) and a knife-pared lamp (Fig. 7:11), all types that were in use during the Early Roman period, particularly in the time between the revolts against Rome (from the last third of the first century to the first third of the second century CE). In addition, the presence of stone vessels (Figs. 7:12–15; 10) indicates that the chamber was used by a Jewish population in the Early Roman period, until the time of the Bar Kokhba uprising (Magen 2002:163–164). Chamber E was eventually connected to three other spaces (F–H), when part of its northern wall was removed. A blocked shaft served as an opening to Chambers F and G, which were probably used as an underground storage-complex in the Early Roman period (Fig. 11). Two narrow openings in the upper part of the northern walls of Chambers F and H facilitated entry to an adjacent underground storage complex, which comprises an entrance corridor (J) whose opening was blocked, and two storerooms (I, K). Room K is square (1.2 × 1.2 m), and a dead-end tunnel (k-k; length 3.5 m) extends from it. A tunnel (e-1; length c. 9 m, average width 0.6 m, height 0.9 m), which forms a number of 90° bends, was hewn in the southwestern corner of Chamber E. It was hewn beneath Corridor A, and after 7 m breached the upper part of the cistern’s wall, making it possible to secretly draw water (see above). The tunnel leads toward a series of underground chambers (L–O), which were apparently used as two adjacent storage systems, and eventually joined when the system was converted to a hiding refuge. Chamber L was accessible through a shaft in the ceiling of Chamber M. It seems that Chamber N, which had niches in it walls, was reached by way of space O—a shaft that led to the surface. 
The architectural plan and the ceramic finds, make it possible to reconstruct several of the phases in the complex. Initially, a subterranean complex that housed an oil press was hewn, in the shape of a clover-leaf. It consisted of a corridor (A), an oil press (B, C), a cistern (D) and a chamber (E), and should apparently be dated to the Hellenistic or Early Roman period. In the second phase, during the Early Roman period, underground storerooms were constructed next to the oil press complex; these were reached by way of shafts and narrow corridors (F–O). Similar complexes were discovered at numerous settlements from the Late Second Temple period in Judah, for example, at Horbat ‘Ethri (Zissu and Ganor 2002:20–21). It seems that prior to the Bar Kokhba uprising, changes were made to the complex—all the spaces were connected by narrow winding tunnels, ancient openings were blocked, and an access way was constructed to ensure the possibility of drawing water surreptitiously. It was presumably during the preparation of the complex for the uprising, that Corridor A was also blocked, and movement between the wings of the complex was by way of Chamber B. A diverse pottery assemblage from this period reflects the intensive use of the chambers. Later, perhaps during the Byzantine period, the oil-press chamber (B) was converted to a quarry; its floor was lowered, and the oil press components were removed. The engraved crosses that were discovered in Chambers B and D indicate activity that took place in the complex during the Byzantine period, when it may have been used as a hermitage, or for quarrying building stones.